USE flag index

What are USE flags?
For more information on the idea behind USE flags and how to use them, please see our documentation.

Global USE flags

Flag Description
3dfx Enable support for Voodoo chipsets, also called as 3DFX and TDFX
X Add support for X11
Xaw3d Add support for the 3d athena widget set
a52 Enable support for decoding ATSC A/52 streams used in DVD
aac Enable support for MPEG-4 AAC Audio
aalib Add support for media-libs/aalib (ASCII-Graphics Library)
accessibility Add support for accessibility (eg 'at-spi' library)
acl Add support for Access Control Lists
acpi Add support for Advanced Configuration and Power Interface
adns Add support for asynchronous DNS resolution
afs Add OpenAFS support (distributed file system)
alsa Add support for media-libs/alsa-lib (Advanced Linux Sound Architecture)
altivec Add support for optimizations for G4 and G5/ppc970 processors
ao Use libao audio output library for sound playback
apache2 Add Apache2 support
apm Add APM (Advanced Power Management) support
aqua Include support for the Mac OS X Aqua (Carbon/Cocoa) GUI
atm Enable Asynchronous Transfer Mode protocol support
audiofile Add support for libaudiofile where applicable
audit Enable support for Linux audit subsystem using sys-process/audit
avahi Add avahi/Zeroconf support
ayatana Build in support for Ayatana notification using the libindicate or libappindicator plugin
bash-completion Enable bash-completion support
berkdb Add support for sys-libs/db (Berkeley DB for MySQL)
bidi Enable bidirectional language support
big-endian Big-endian toolchain support
bindist Flag to enable or disable options for prebuilt (GRP) packages (eg. due to licensing issues)
blas Add support for the virtual/blas numerical library
bluetooth Enable Bluetooth Support
bootstrap !!internal use only!! DO NOT SET THIS FLAG YOURSELF!, used during original system bootstrapping [make stage2]
branding Enable Gentoo specific branding
build !!internal use only!! DO NOT SET THIS FLAG YOURSELF!, used for creating build images and the first half of bootstrapping [make stage1]
bzip2 Use the bzlib compression library
cairo Enable support for the cairo graphics library
calendar Add support for calendars (not using mcal!)
canna Add support for the Canna kana to kanji conversion engine
caps Use Linux capabilities library to control privilege
cdb Add support for the CDB database engine from the author of qmail
cdda Add Compact Disk Digital Audio (Standard Audio CD) support
cddb Access cddb servers to retrieve and submit information about compact disks
cdinstall Copy files from the CD rather than asking the user to copy them, mostly used with games
cdparanoia Enable cdparanoia (audio CD ripper) support
cdr Add support for CD writer hardware
cgi Add CGI script support
cjk Add support for Multi-byte character languages (Chinese, Japanese, Korean)
clamav Add support for Clam AntiVirus software (usually with a plugin)
connman Add support for net-misc/connman
coreaudio Build the CoreAudio driver on Mac OS X systems
cracklib Support for cracklib strong password checking
crypt Add support for encryption -- using mcrypt or gpg where applicable
cscope Enable cscope interface -- in vim for example
css Enable reading of encrypted DVDs
cups Add support for CUPS (Common Unix Printing System)
curl Add support for client-side URL transfer library
custom-cflags Build with user-specified CFLAGS (unsupported)
cvs Enable CVS (Concurrent Versions System) integration
cxx Build support for C++ (bindings, extra libraries, code generation, ...)
dbi Enable dev-db/libdbi (database-independent abstraction layer) support
dbm Add support for generic DBM databases
dbus Enable dbus support for anything that needs it (gpsd, gnomemeeting, etc)
debug Enable extra debug codepaths, like asserts and extra output. If you want to get meaningful backtraces see https://wiki.gentoo.org/wiki/Project:Quality_Assurance/Backtraces
dedicated Add support for dedicated game servers (some packages do not provide clients and servers at the same time)
dga Add DGA (Direct Graphic Access) support for X
directfb Add support for DirectFB layer (library for FB devices)
djvu Support DjVu, a PDF-like document format esp. suited for scanned documents
doc Add extra documentation (API, Javadoc, etc). It is recommended to enable per package instead of globally
dri Enable direct rendering: used for accelerated 3D and some 2D, like DMA
dts Enable DTS Coherent Acoustics decoder support
dv Enable support for a codec used by many camcorders
dvb Add support for DVB (Digital Video Broadcasting)
dvd Add support for DVDs
dvdr Add support for DVD writer hardware (e.g. in xcdroast)
eds Enable support for Evolution-Data-Server (EDS)
emacs Add support for GNU Emacs
emboss Add support for the European Molecular Biology Open Software Suite
encode Add support for encoding of audio or video files
enscript Add enscript support to colourize code stored in the repository
evo Add support for mail-client/evolution
examples Install examples, usually source code
exif Add support for reading EXIF headers from JPEG and TIFF images
expat Enable the use of dev-libs/expat for XML parsing
fam Enable FAM (File Alteration Monitor) support
fastcgi Add support for the FastCGI interface
fbcon Add framebuffer support for the console, via the kernel
ffmpeg Enable ffmpeg/libav-based audio/video codec support
fftw Use FFTW library for computing Fourier transforms
filecaps Use Linux file capabilities to control privilege rather than set*id (this is orthogonal to USE=caps which uses capabilities at runtime e.g. libcap)
firebird Add support for the Firebird relational database
flac Add support for FLAC: Free Lossless Audio Codec
fltk Add support for the Fast Light Toolkit gui interface
fontconfig Support for configuring and customizing font access via media-libs/fontconfig
fortran Add support for fortran
freetds Add support for the TDS protocol to connect to MSSQL/Sybase databases
freewnn Add support for FreeWnn kana to kanji conversion engine
ftp Add FTP (File Transfer Protocol) support
gcj Enable building with gcj (The GNU Compiler for the Javatm Programming Language)
gd Add support for media-libs/gd (to generate graphics on the fly)
gdbm Add support for sys-libs/gdbm (GNU database libraries)
geoip Add geoip support for country and city lookup based on IPs
geolocation Enable physical position determination
ggi Add support for media-libs/libggi (non-X video api/drivers)
gif Add GIF image support
gimp Build a plugin for the GIMP
git Enable git (version control system) support
glut Build an OpenGL plugin using the GLUT library
gmp Add support for dev-libs/gmp (GNU MP library)
gnome Add GNOME support
gnome-keyring Enable support for storing passwords via gnome-keyring
gnuplot Enable support for gnuplot (data and function plotting)
gnutls Prefer net-libs/gnutls as SSL/TLS provider (ineffective with USE=-ssl)
gphoto2 Add digital camera support
gpm Add support for sys-libs/gpm (Console-based mouse driver)
gps Add support for Global Positioning System
graphicsmagick Build and link against GraphicsMagick instead of ImageMagick (might require USE=imagemagick if optional)
graphviz Add support for the Graphviz library
gsl Use the GNU scientific library for calculations
gsm Add support for the gsm lossy speech compression codec
gstreamer Add support for media-libs/gstreamer (Streaming media)
gtk Add support for x11-libs/gtk+ (The GIMP Toolkit)
gtk-doc Build and install gtk-doc based developer documentation for dev-util/devhelp, IDE and offline use
guile Add support for the guile Scheme interpreter
gzip Compress files with Lempel-Ziv coding (LZ77)
handbook Enable handbooks generation for packages by KDE
hardened Activate default security enhancements for toolchain (gcc, glibc, binutils)
hddtemp Enable monitoring of hdd temperature (app-admin/hddtemp)
hdf5 Add support for the Hierarchical Data Format v5
headers-only Install only C headers instead of whole package. Mainly used by sys-devel/crossdev for toolchain bootstrap.
hscolour Include coloured haskell sources to generated documentation (dev-haskell/hscolour)
ibm Add support for IBM ppc64 specific systems
iconv Enable support for the iconv character set conversion library
icq Enable ICQ IM protocol support
icu Enable ICU (Internationalization Components for Unicode) support, using dev-libs/icu
idn Enable support for Internationalized Domain Names
ieee1394 Enable FireWire/iLink IEEE1394 support (dv, camera, ...)
imagemagick Enable optional support for the ImageMagick or GraphicsMagick image converter
imap Add support for IMAP (Internet Mail Application Protocol)
imlib Add support for imlib, an image loading and rendering library
infiniband Enable Infiniband RDMA transport support
inotify Enable inotify filesystem monitoring support
introspection Add support for GObject based introspection
iodbc Add support for iODBC library
ios Enable support for Apple's iDevice with iOS operating system (iPad, iPhone, iPod, etc)
ipod Enable support for iPod device access
ipv6 Add support for IP version 6
jack Add support for the JACK Audio Connection Kit
java Add support for Java
javascript Enable javascript support
jbig Enable jbig-kit support for tiff, Hylafax, ImageMagick, etc
jemalloc Use dev-libs/jemalloc for memory management
jingle Enable voice calls for jabber
jit Enable just-in-time compilation for improved performance. May prevent use of some PaX memory protection features in Gentoo Hardened.
joystick Add support for joysticks in all packages
jpeg Add JPEG image support
jpeg2k Support for JPEG 2000, a wavelet-based image compression format
kde Add support for KDE (K Desktop Environment)
kerberos Add kerberos support
ladspa Enable the ability to support ladspa plugins
lame Prefer using LAME libraries for MP3 encoding support
lapack Add support for the virtual/lapack numerical library
lash Add LASH Audio Session Handler support
latex Add support for LaTeX (typesetting package)
lcms Add lcms support (color management engine)
ldap Add LDAP support (Lightweight Directory Access Protocol)
libass SRT/SSA/ASS (SubRip / SubStation Alpha) subtitle support
libav Prefer libav over ffmpeg whenever both are supported
libcaca Add support for colored ASCII-art graphics
libedit Use the libedit library (replacement for readline)
libffi Enable support for Foreign Function Interface library
libnotify Enable desktop notification support
libressl Use dev-libs/libressl instead of dev-libs/openssl when applicable (see also the ssl useflag)
libsamplerate Build with support for converting sample rates using libsamplerate
libwww Add libwww support (General purpose WEB API)
lirc Add support for lirc (Linux's Infra-Red Remote Control)
livecd !!internal use only!! DO NOT SET THIS FLAG YOURSELF!, used during livecd building
lm_sensors Add linux lm_sensors (hardware sensors) support
lua Enable Lua scripting support
luajit Use dev-lang/luajit instead of dev-lang/lua (ineffective with USE=-lua)
lzma Support for LZMA (de)compression algorithm
lzo Enable support for lzo compression
m17n-lib Enable m17n-lib support
mad Add support for mad (high-quality mp3 decoder library and cli frontend)
maildir Add support for maildir (~/.maildir) style mail spools
matroska Add support for the matroska container format (extensions .mkv, .mka and .mks)
mbox Add support for mbox (/var/spool/mail) style mail spools
memcached Add support for memcached
memlimit Add memory usage limiting in supporting programs
mhash Add support for the mhash library
migemo Enable migemo support for Japanese
mikmod Add libmikmod support to allow playing of SoundTracker-style music files
milter Add sendmail mail filter (milter) support
minimal Install a very minimal build (disables, for example, plugins, fonts, most drivers, non-critical features)
mmap Add mmap (memory map) support
mms Support for Microsoft Media Server (MMS) streams
mng Add support for libmng (MNG images)
modplug Add libmodplug support for playing SoundTracker-style music files
modules Build the kernel modules
mono Build Mono bindings to support dotnet type stuff
motif Add support for the Motif toolkit
mp3 Add support for reading mp3 files
mp4 Support for MP4 container format
mpeg Add libmpeg3 support to various packages
mpi Add MPI (Message Passing Interface) layer to the apps that support it
mplayer Enable mplayer support for playback or encoding
msn Enable MSN Messenger IM protocol support
mssql Add support for Microsoft SQL Server database
mtp Enable support for Media Transfer Protocol
mule Add multi-language support to XEmacs
multilib On 64bit systems, if you want to be able to compile 32bit and 64bit binaries
musepack Enable support for the musepack audio codec
musicbrainz Lookup audio metadata using MusicBrainz community service (musicbrainz.org)
mysql Add mySQL Database support
mysqli Add support for the improved mySQL libraries
nas Add support for network audio sound
ncurses Add ncurses support (console display library)
neXt Enable neXt toolkit
neon Enable optimization support for ARM NEON processors
netboot Enable network booting
netcdf Enable NetCDF data format support
networkmanager Enable net-misc/networkmanager support
nis Support for NIS/YP services
nls Add Native Language Support (using gettext - GNU locale utilities)
nntp Add support for newsgroups (Network News Transfer Protocol)
nocd Install all files required to run the application without a CD mounted
nptl Enable support for Native POSIX Threads Library, the new threading module (requires linux-2.6 or better usually)
nsplugin Build plugin for browsers supporting the Netscape plugin architecture (that is almost any modern browser)
ocaml Add support/bindings for the Ocaml language
ocamlopt Enable ocamlopt support (ocaml native code compiler) -- Produces faster programs (Warning: you have to disable/enable it at a global scale)
oci8 Add Oracle 8 Database Support
oci8-instant-client Use dev-db/oracle-instantclient-basic as Oracle provider instead of requiring a full Oracle server install
odbc Add ODBC Support (Open DataBase Connectivity)
offensive Enable potentially offensive items in packages
ofx Enable support for importing (and exporting) OFX (Open Financial eXchange) data files
ogg Add support for the Ogg container format (commonly used by Vorbis, Theora and flac)
openal Add support for the Open Audio Library
openexr Support for the OpenEXR graphics file format
opengl Add support for OpenGL (3D graphics)
openmp Build support for the OpenMP (support parallel computing), requires >=sys-devel/gcc-4.2 built with USE="openmp"
opus Enable Opus audio codec support
oracle Enable Oracle Database support
orc Use dev-lang/orc for just-in-time optimization of array operations
osc Enable support for Open Sound Control
oscar Enable Oscar (AIM/ICQ) IM protocol support
oss Add support for OSS (Open Sound System)
pam Add support for PAM (Pluggable Authentication Modules) - DANGEROUS to arbitrarily flip
pch Enable precompiled header support for faster compilation at the expense of disk space and memory (>=sys-devel/gcc-3.4 only)
pcmcia Add support for PCMCIA slots/devices found on laptop computers
pcre Add support for Perl Compatible Regular Expressions
pda Add support for portable devices
pdf Add general support for PDF (Portable Document Format), this replaces the pdflib and cpdflib flags
perl Add optional support/bindings for the Perl language
php Include support for the PHP language
pie Build programs as Position Independent Executables (a security hardening technique)
plasma Build optional KDE plasma addons
plotutils Add support for plotutils (library for 2-D vector graphics)
png Add support for libpng (PNG images)
policykit Enable PolicyKit authentication support
portaudio Add support for the crossplatform portaudio audio API
posix Add support for POSIX-compatible functions
postgres Add support for the postgresql database
postscript Enable support for the PostScript language (often with ghostscript-gpl or libspectre)
ppds Add support for automatically generated ppd (printing driver) files
prefix Defines if a Gentoo Prefix offset installation is used
prelude Add support/bindings for the Prelude Intrusion Detection System
profile Add support for software performance analysis (will likely vary from ebuild to ebuild)
pulseaudio Add support for PulseAudio sound server
python Add optional support/bindings for the Python language
qdbm Add support for the qdbm (Quick Database Manager) library
qmail-spp Add support for qmail SMTP plugins
qt4 Add support for the Qt GUI/Application Toolkit version 4.x
qt5 Add support for the Qt 5 application and UI framework
quicktime Add support for OpenQuickTime
radius Add support for RADIUS authentication
raw Add support for raw image formats
rdp Enables RDP/Remote Desktop support
readline Enable support for libreadline, a GNU line-editing library that almost everyone wants
recode Enable support for the GNU recode library
rss Enable support for RSS feeds
ruby Add support/bindings for the Ruby language
samba Add support for SAMBA (Windows File and Printer sharing)
sasl Add support for the Simple Authentication and Security Layer
savedconfig Use this to restore your config from /etc/portage/savedconfig ${CATEGORY}/${PN}. Make sure your USE flags allow for appropriate dependencies
scanner Add support for scanner hardware (e.g. build the sane frontend in kdegraphics)
sctp Support for Stream Control Transmission Protocol
sdl Add support for Simple Direct Layer (media library)
seamonkey Add support for the Seamonkey web-browser
seccomp Enable seccomp (secure computing mode) to perform system call filtering at runtime to increase security of programs
selinux !!internal use only!! Security Enhanced Linux support, this must be set by the selinux profile or breakage will occur
semantic-desktop Cross-KDE support for semantic search and information retrieval
session Add persistent session support
shorten Add support for the shorten audio compressor
skey Enable S/Key (Single use password) authentication support
slang Add support for the slang text display library (it's like ncurses, but different)
slp Add Service Locator Protocol support
smartcard Enable smartcard support
smp Enable support for multiprocessors or multicore systems
sndfile Add support for libsndfile
snmp Add support for the Simple Network Management Protocol if available
soap Add support for SOAP (Simple Object Access Protocol)
sockets Add support for tcp/ip sockets
socks5 Add support for the socks5 proxy
sound Enable sound support
source Zip the sources and install them
sox Add support for Sound eXchange (SoX)
speex Add support for the speex audio codec (used for speech)
spell Add dictionary support
sqlite Add support for sqlite - embedded sql database
ssl Add support for SSL/TLS connections (Secure Socket Layer / Transport Layer Security)
startup-notification Enable application startup event feedback mechanism
static !!do not set this during bootstrap!! Causes binaries to be statically linked instead of dynamically
static-libs Build static versions of dynamic libraries as well
subversion Enable subversion (version control system) support
suid Enable setuid root program, with potential security risks
svg Add support for SVG (Scalable Vector Graphics)
svga Add support for SVGAlib (graphics library)
symlink Force kernel ebuilds to automatically update the /usr/src/linux symlink
syslog Enable support for syslog
systemd Enable use of systemd-specific libraries and features like socket activation or session tracking
szip Use the szip compression library
taglib Enable tagging support with taglib
tcl Add support the Tcl language
tcmalloc Use the dev-util/google-perftools libraries to replace the malloc() implementation with a possibly faster one
tcpd Add support for TCP wrappers
test Enable dependencies and/or preparations necessary to run tests (usually controlled by FEATURES=test but can be toggled independently)
theora Add support for the Theora Video Compression Codec
threads Add threads support for various packages. Usually pthreads
tidy Add support for HTML Tidy
tiff Add support for the TIFF image format
timidity Build with Timidity++ (MIDI sequencer) support
tk Add support for Tk GUI toolkit
truetype Add support for FreeType and/or FreeType2 fonts
uclibc Enable uclibc specific patches and build or link uclibc
udev Enable virtual/udev integration (device discovery, power and storage device support, etc)
udisks Enable storage management support (automounting, volume monitoring, etc)
unicode Add support for Unicode
unwind Add support for call stack unwinding and function name resolution
upnp Enable UPnP port mapping support
upnp-av Enable UPnP audio/video streaming support
upower Enable power management support
usb Add USB support to applications that have optional USB support (e.g. cups)
v4l Enable support for video4linux (using linux-headers or userspace libv4l libraries)
vaapi Enable Video Acceleration API for hardware decoding
vala Enable bindings for dev-lang/vala
vanilla Do not add extra patches which change default behaviour; DO NOT USE THIS ON A GLOBAL SCALE as the severity of the meaning changes drastically
vcd Video CD support
vdpau Enable the Video Decode and Presentation API for Unix acceleration interface
vhosts Add support for installing web-based applications into a virtual-hosting environment
videos Install optional video files (used in some games)
vim-syntax Pulls in related vim syntax scripts
vnc Enable VNC (remote desktop viewer) support
vorbis Add support for the OggVorbis audio codec
wavpack Add support for wavpack audio compression tools
wayland Enable dev-libs/wayland backend
webkit Add support for the WebKit HTML rendering/layout engine
webp Add support for the WebP image format
wifi Enable wireless network functions
wmf Add support for the Windows Metafile vector image format
wxwidgets Add support for wxWidgets/wxGTK GUI toolkit
x264 Enable h264 encoding using x264
xattr Add support for extended attributes (filesystem-stored metadata)
xcb Support the X C-language Binding, a replacement for Xlib
xcomposite Enable support for the Xorg composite extension
xemacs Add support for XEmacs
xface Add xface support used to allow a small image of xface format to be included in an email via the header 'X-Face'
xft Build with support for XFT font renderer (x11-libs/libXft)
xine Add support for the XINE movie libraries
xinerama Add support for querying multi-monitor screen geometry through the Xinerama API
xinetd Add support for the xinetd super-server
xml Add support for XML files
xmlrpc Support for xml-rpc library
xmp Enable support for Extensible Metadata Platform (Adobe XMP)
xmpp Enable support for Extensible Messaging and Presence Protocol (XMPP) formerly known as Jabber
xosd Sends display using the X On Screen Display library
xpm Add support for XPM graphics format
xscreensaver Add support for XScreenSaver extension
xv Add in optional support for the Xvideo extension (an X API for video playback)
xvid Add support for xvid.org's open-source mpeg-4 codec
yahoo Enable Yahoo Messenger IM protocol support
yaz Add in optional support for the Z39.50 Protocol for Information Retrieval (YAZ)
zeroconf Support for DNS Service Discovery (DNS-SD)
zip Enable support for ZIP archives
zlib Add support for zlib (de)compression
zsh-completion Enable zsh completion support

Local USE flags

app-accessibility

brltty

api build brltty's application program interface
beeper support the console tone generator
contracted-braille support in-line contracted braille
fm support for the sound card synthesizer
midi support the musical instrument digital interface
pcm support for sound card digital audio
speech speech support

eflite

16k_voice Use a higher-quality voice.

emacspeak

espeak Adds support for the espeak tts engine

festival-it

mbrola Adds support for mbrola voices

freetts

jsapi build Java Speech API (JSAPI)
mbrola Adds support for mbrola voices

orca

braille Enable braille support

simon

opencv Use media-libs/opencv
pim Enable support for KDE PIM resources integration
sphinx Build sphinx backend (pulls app-accessibility/julius if disabled

speech-dispatcher

espeak Adds support for espeak speech engine
flite Adds support for flite speech engine

speechd-el

brltty brltty support

app-admin

bcfg2

cheetah Include dev-python/cheetah support
genshi Include dev-python/genshi support
server Installs scripts to be used on the server-side of this app

calamares

pythonqt Enable PythonQt-based module interface

clsync

cgroups Use cgroups to limit /dev access.
cluster Enable clustering support (allows master-master clsync on multiple hosts). Not fully implemented yet.
control-socket Enable AF_UNIX control socket support.
extra-debug Enable extra debugging. This will hurt performance badly. Be ready for tons of output.
extra-hardened Enable extra security checks. This will hurt performance.
gio Enable GIO for FS monitoring (glib based alternative to inotify interface, not recommended; if both are compiled, may be selected at runtime).
highload-locks Allows to use spinlocks for short delays instead of mutexes, but only on SMP systems.
namespaces Enable namespaces isolation.

conky

apcupsd Enable support for sys-power/apcupsd
audacious Enable monitoring of music played by media-sound/audacious
cmus Enable monitoring of music played by media-sound/cmus
eve Enable support for the eve-online skill monitor
ical Enable support for events from iCalendar (RFC 5545) files using dev-libs/libical
iostats Enable support for per-task I/O statistics
irc Enable support for displaying everything from an irc channel using net-libs/libircclient
lua-cairo Enable if you want Lua Cairo bindings
lua-imlib Enable if you want Lua Imlib2 bindings
lua-rsvg Enable if you want Lua RSVG bindings
math Enable support for glibc's libm math library
moc Enable monitoring of music played by media-sound/moc
mpd Enable monitoring of music controlled by media-sound/mpd
nano-syntax Enable syntax highlighting for app-editors/nano
nvidia Enable reading of nvidia card temperature sensors via x11-drivers/nvidia-drivers
portmon Enable support for tcp (ip4) port monitoring
thinkpad Enable support for IBM/Lenovo notebooks
weather-metar Enable support for metar weather service
weather-xoap Enable support for metar and xoap weather service
webserver Enable support to act as a webserver serving conkys output using net-libs/libmicrohttpd
xmms2 Enable monitoring of music played by media-sound/xmms2

diamond

mongo Enable MongoDB support
redis Enable Redis support

diradm

automount Support for automount data in LDAP
irixpasswd Support for storing separate IRIX passwords

elektra

augeas Enable plugin for reading and writing configuration files with help from Augeas
ini Enable new, advanced ini support
simpleini Enable simpleini support
uname Enable uname information for the key database
yajl Enable yajl support

gkrellm

X Build both the X11 gui (gkrellm) and the server (gkrellmd). Disabling this flag builds the server only
gnutls Enable SSL support for mail checking with net-libs/gnutls (overrides 'ssl' USE flag)
hddtemp Enable monitoring harddrive temperatures via app-admin/hddtemp
lm_sensors Enable monitoring sensors via sys-apps/lm_sensors
ntlm Enable NTLM authentication for mail checking with net-libs/libntlm
ssl Enable SSL support for mail checking with dev-libs/openssl

glance

swift Adds swift storage support

gtkdiskfree

gtk2 Support GTK+ 2.x instead of GTK+ 3.x

hddtemp

network-cron Monthly cronjob to update hddtemp.db.

keepass

aot Generate native code at build time, rather than runtime.

keepassxc

autotype Add support to autotype the passwords into other applications
browser Enables browser plugin support
network Enable network support
yubikey Enable database unlocking via YubiKey.

lastpass-cli

X Use x11-misc/xclip or x11-misc/xsel to copy passwords to the clipboard.
pinentry Use app-crypt/pinentry to prompt for passwords.

logrotate

acl Installs acl support
cron Installs cron file
selinux Installs Security Enhanced Linux support

logstash-bin

x-pack Enable additional features (may need a license)

matter

entropy Add Entropy support

mcollective

client Install client utilities

mms-agent

monitoring Install the monitoring agent

openrc-settingsd

systemd Use the versions of dbus and polkit files provided by sys-apps/systemd

packagekit-base

command-not-found Enable packagekit support on shell "command not found"
cron Install cron script for auto-update
elogind Enable elogind support to get user session
entropy Enable Entropy backend

pass

X Use x11-misc/xclip to copy passwords to the clipboard.
dmenu Add support for x11-misc/dmenu with the 'passmenu' program.
fish-completion Enable fish completion support.
git Use dev-vcs/git for password revisions.
importers Allow importing passwords from other password managers using various contributed scripts.

pass-otp

qrcode Add support for qrcodes using media-gfx/qrencode

passwordsafe

minimal Avoid collision with app-misc/pwsafe
qr Enable QR code password display
xml Enable XML import support
yubikey Enable support for Yubikey

prelude-manager

dbx Enables Prelude Manager storing Prelude alerts into database through dev-libs/libpreludedb .
tcpwrapper Enables Prelude Manager using tcp wrapper. It requires sys-apps/tcp-wrappers .

puppet

augeas Enable augeas support
diff Enable diff support
experimental Add patches for things in testing
rrdtool Enable rrdtool support
shadow Enable shadow support

puppet-agent

puppetdb Adds puppetdb support

puppetserver

puppetdb Adds support for connecting to puppetdb

pwgen

livecd Install init script for root password scrambling on boot

pwman3

mongodb Add support for MongoDB

rsyslog

curl Enable http_request() function in RainerScript (requires net-misc/curl)
dbi Build the general database output module (requires dev-db/libdbi)
elasticsearch Build the Elasticsearch output module (requires net-misc/curl)
gcrypt Add support for encrypted log files using dev-libs/libgcrypt
gnutls Build the GnuTLS network stream driver (requires net-libs/gnutls)
grok Build the grok modify module (requires dev-libs/grok)
kafka Build the Apache Kafka input/output module (requires dev-libs/librdkafka)
kerberos Build the GSSAPI input and output module (requires virtual/krb5)
kubernetes Build the kubernetes modify plugin (requires net-misc/curl)
libressl Use dev-libs/libressl instead of dev-libs/openssl (you still need to enable functionality which requires OpenSSL)
mdblookup Build the MaxMind DB lookup message modify plugin using dev-libs/libmaxminddb
mongodb Build the MongoDB output module (requires dev-libs/libmongo-client)
mysql Build the MySQL database output module (requires virtual/mysql)
normalize Build the normalize modify module (requires dev-libs/libee and dev-libs/liblognorm)
omhttp Build the http output module (requires net-misc/curl)
omhttpfs Build the httpfs output module (requires net-misc/curl)
omudpspoof Build the udpspoof output module (requires net-libs/libnet)
openssl Build the OpenSSL network stream driver (requires dev-libs/openssl)
postgres Build the PostgreSQL database output module (requires dev-db/postgresql)
rabbitmq Build the RabbitMQ output module (requires net-libs/rabbitmq-c)
redis Build the Redis output module using (requires dev-libs/hiredis)
relp Build the Reliable Event Logging Protocol (RELP) output module (requires dev-libs/librelp)
rfc3195 Build the rfc3195 input module (requires dev-libs/liblogging)
rfc5424hmac Build the rfc5424hmac modify module (requires dev-libs/openssl or dev-libs/libressl)
snmp Build the snmp modify and output module (requires net-analyzer/net-snmp)
ssl Add support for encrypted client/server communication (requires net-libs/gnutls)
systemd Build the journal input and output module (requires sys-apps/systemd)
usertools Installs the user tools (rsgtutil, rscryutil...) corresponding to the set USE flags
uuid Include UUIDs in messages (requires sys-apps/util-linux)
xxhash Enable xxHash support in fmhash module (requires dev-libs/xxhash)
zeromq Build the ZeroMQ input and output modules (requires net-libs/czmq)

sagan

libdnet Add support for dev-libs/libdnet
lognorm Add support for log/rules normalizations via dev-libs/liblognorm
pcap Add support for network packet capture via net-libs/libpcap
smtp Build witch SMTP (E-Mail) support
snort Add support to interact with Snort IDE using net-analyzer/snortsam'

sagan-rules

lognorm Install normalize rules support with dev-libs/liblognorm

salt

cherrypy Enable support for using cherrypy.
gnupg Enable support for gnupg via python-gnupg.
keyring Enable support for keyrings via python-keyring.
libcloud Enable salt-cloud support via libcloud.
libvirt Support managing virtual machines with app-emulation/libvirt.
mako Add support for using the mako template engine for parsing salt states.
mongodb Support returning data to a mongodb server.
neutron Support the OpenStack neutron network service.
nova Enable support for the OpenStack Nova API
openssl Add support for using TLS via OpenSSL.
portage Add support for package state enforcement using sys-apps/portage
raet Add support for the new RAET transport.
redis Support returning data to a redis database.
timelib Use timelib to parse english textual date descriptions.
zeromq Add support for the zeromq transport.

sudo

gcrypt Use SHA2 from dev-libs/libgcrypt instead of sudo's internal SHA2
offensive Let sudo print insults when the user types the wrong password
openssl Use SHA2 from dev-libs/openssl instead of sudo's internal SHA2
sendmail Allow sudo to send emails with sendmail
sssd Add System Security Services Daemon support

sysklogd

logrotate use app-admin/logrotate for rotating logs rather than custom cron scripts

syslog-ng

amqp Enable support for AMQP destinations
geoip2 Add support for geo lookup based on IPs via dev-libs/libmaxminddb
http Enable support for HTTP destinations
json Enable support for JSON template formatting via dev-libs/json-c
mongodb Enable support for mongodb destinations
pacct Enable support for reading Process Accounting files (EXPERIMENTAL, Linux only)
redis Enable support for Redis destinations
smtp Enable support for SMTP destinations
spoof-source Enable support for spoofed source addresses

sysstat

isag Install isag, the Interactive System Activity Graph tool

systemrescuecd-x86

isohybrid Pass downloaded images through isohybrid in order to make it possible to copy them directly to USB media and boot (requires sys-boot/syslinux at build time).

testdisk

ewf Include ewf library
ntfs Include the ability to read NTFS filesystems
reiserfs Include reiserfs reading ability

tripwire

ssl Adds support for Secure Socket Layer connections
static Builds the package statically
tools Installs app-admin/mktwpol, providing scripts for the installation/setup of tripwire, including generating the tripwire policy file and maintenance of the tripwire database

ulogd

json Build JSON output plugin to save packets in JSON file format
nfacct Build NFACCT input plugin to support traffic accounting via nfnetlink_acct
nfct Build NFCT input plugin to support stateful flow-based logging via nfnetlink_conntrack
nflog Build NFLOG input plugin to support stateless packet-based logging via nfnetlink_log
pcap Build PCAP output plugin to save packets in libpcap file format
ulog Build ULOG input plugin to support deprecated packet-based logging via ULOG target

webalizer

xtended Include the 404 extension

webapp-config

portage Propagete python_targets dependencies to sys-apps/portage

yaala

storable Support for persistence of Perl data structures.

app-antivirus

clamav

clamdtop A Top like tool which shows what clamd is currently scanning amongst other things
metadata-analysis-api Enables collection of file property metadata using ClamAV API for analysis by ClamAV bytecode programs.
system-libmspack Use system libmspack instead of built in
xml DMG and XAR support

clamtk

kde Install the Dolphin plugin.
nautilus Install the Nautilus plugin.
nemo Install the Nemo plugin.
thunar Install the Thunar plugin.

app-arch

cabextract

extras Install experimental extra tools: wince_info and wince_rename for examining and processing Windows CE installation cabinet header files; cabinfo for examining the structure of a cab file.

cfv

bittorrent Enable support for checking .torrent files

deltarpm

system-zlib Use system sys-libs/zlib. Do not enable features of rsync friendly.

dpkg

libmd Use app-crypt/libmd library for message digest functions
update-alternatives Install update-alternatives

dump

ermt encrypted rmt support
uuid Enable UUID support

engrampa

caja Enable engrampa to integrate with mate-base/caja by providing entries in its context menu
magic Enable filetype auto-detection via sys-apps/file
packagekit Enable support for installing via app-admin/packagekit based on archive type

file-roller

nautilus Build contextual menu extension for gnome-base/nautilus.
packagekit Enable support for the distro-neutral package manager GUI app-admin/packagekit

gzip

pic disable optimized assembly code that is not PIC friendly

innoextract

debug Enable debug logging and the --debug command-line option
lzma Enable support for extracting lzma-compressed installers using app-arch/xz-utils

libarchive

bzip2 Allow accessing bzip2-compressed archives through libbz2 (which comes with app-arch/bzip2). This only affects libarchive's native support: bsdtar will keep using bunzip2 as a filter if that's not built-in.
e2fsprogs Use file flags from sys-fs/e2fsprogs headers instead of virtual/os-headers headers
lz4 Enable support for LZ4 compression using app-arch/lz4
nettle Use dev-libs/nettle as crypto backend
zlib Allow accessing gzip-compressed archives through sys-libs/zlib. This only affects libarchive's native support: bsdtar will keep using gunzip as a filter if that's not built-in. It's also needed for supporting extraction of ZIP files.

p7zip

rar Enable support for non-free rar decoder

pbzip2

symlink Install symlinks which override app-arch/bzip2 implementation

pigz

symlink Install symlinks which override app-arch/gzip implementation

rar

all_sfx Install all SFX (Self-Extracting) files rather than just the native format (allows creation of Windows EXEs on Linux ELF systems)

rpm

zstd Enable support for ZSTD compression using app-arch/zstd

tar

minimal just install `tar`

unzip

natspec Use dev-libs/libnatspec to correctly decode non-ascii file names archived in Windows.

wimlib

fuse Use fuse libraries
iso Install app-cdr/cdrtools in order to prepare iso images
ntfs Use libntfs-3g library from sys-fs/ntfs3g
openssl Use the SHA-1 message digest from libcrypto instead of compilling another implementation
yasm Use yasm assembler instead of nasm

xz-utils

extra-filters Build additional filters that are not used in any of the default xz presets. This includes delta and BCJ coders, additional match finders and SHA256 checks.

zip

natspec Use dev-libs/libnatspec to correctly decode non-ascii file names archived in Windows.

zstd

lz4 Enable support for LZ4 compression using app-arch/lz4

app-backup

amanda

ndmp Support for the NDMP protocol
s3 Support for backing up to the Amazon S3 system
xfs Support for backing up raw XFS filesystems using xfsdump

backup-manager

s3 Support for backing up to the Amazon S3 system

bacula

bacula-clientonly Disable DB support, and just build a client
bacula-nodir Disable building of director
bacula-nosd Disable building of storage daemon
logwatch Install support files for logwatch

bareos

cephfs Enable cephfs storage backend
clientonly Only install file-daemon (client)
director Install director
fastlz Enable support vor lz4, lz4hc and lzfast using dev-libs/bareos-fastlzlib
glusterfs Enable glusterfs storage backend
gnutls When ssl is enabled, use GnuTLS instead of OpenSSL
jansson JSON API support using JANSSON for director
lmdb enable build of LMDB support for faster accurate backup
logwatch Install support files for logwatch
ndmp Enable support for NDMP (Network Data Management Protocol)
rados Enable rados storage backend
rados-striper Enable use of rados-striper
scsi-crypto Enable low level SCSI crypto support
sql-pooling Enable SQL pooling support
storage-daemon Install storage daemon (bareos-sd)

btrbk

pv Use sys-apps/pv to enable progress bar functionality

bup

web Support browsing backups via a web interface

dar

dar32 Enables --enable-mode=32 option, which replace infinite by 32 bit integers
dar64 Enables --enable-mode=64 option, which replace infinite by 64 bit integers
gcrypt Enables strong encryption support
gpg Enables usage of asymetric crypto algorithms

deja-dup

nautilus Build gnome-base/nautilus extension

duplicity

s3 Support for backing up to the Amazon S3 system

fsarchiver

lz4 Enable lz4 compression support
zstd Enable zstd compression support

rear

udev Have ReaR start backup when attaching your USB drive.

snapper

btrfs Include Btrfs support sys-fs/btrfs-progs
ext4 Include Ext4 support sys-fs/e2fsprogs
lvm Enable LVM thinprovisioned snapshots support sys-fs/lvm2
xattr Add support for getting and setting POSIX extended attributes, through sys-apps/attr.

tsm

tsm_cit IBM Tivoli Common Inventory Technology
tsm_hw Difference snapshot support for NetApp and N-Series file servers

zbackup

tartool Install tartool utility

app-benchmarks

filebench

auto-completion Enable command-line autocompletion using dev-libs/libtecla

httperf

idleconn Build with the idleconn program

ramspeed

pic Force shared libraries to be built as PIC (this is slower)

sysbench

aio Enable libaio support

app-cdr

brasero

libburn Enable dev-libs/libburn backend
nautilus Build the gnome-base/nautilus extension
packagekit Enable support for the distro-neutral package manager GUI app-admin/packagekit
playlist Enable support for playlists through dev-libs/totem-pl-parser
tracker Enable audio playlist search using the app-misc/tracker indexer

cdemu

cdemu-daemon Pull app-cdr/cdemu-daemon dependency, useful in chroot environment (bug #315491). Do not disable until you know what you are doing.

dvdisaster

debug Enable memory debugging.

gaffitter

scripts Install additional gaffitter scripts for external programs

mirage2iso

pinentry Support app-crypt/pinentry password input backend.

app-crypt

aespipe

asm Enable assembly modules
cpu_flags_x86_padlock Use VIA padlock instructions, detected at run time, code still works on non-padlock processors

ccid

kobil-midentity Build and install Kobil_mIDentity_switch tool
twinserial Enable twinserial reader

codecrypt

cryptopp Build algorithms that need Crypto++ support dev-libs/crypto++

dehydrated

cron Install cron job to sign/renew non-existent/changed/expiring certificates

eid-mw

dialogs Enable "askaccess" dialog box, by using x11-libs/gtk+
gtk All dialogs are available, by using x11-libs/gtk+
p11-kit Support for app-crypt/p11-kit.
xpi Build and install an extension for Mozilla browsers.

ekeyd

minimal Only install the ekey-egd-linux service rather than the full ekeyd package.
munin Install a plugin for net-analyzer/munin to graph statistical data from ekeyd.
usb Build the libusb-based userland daemon for accessing the EntropyKey (alternative to the CDC USB driver). It is suggested to use this option by default, as the CDC driver in the kernel often seems to be fragile (or the gadget implementation on the EntropyKey is too buggy), and can cause various problems.

gnupg

mta Build mta support using virtual/mta.
smartcard Build scdaemon software. Enables usage of OpenPGP cards. For other type of smartcards, try app-crypt/gnupg-pkcs11-scd. Bring in dev-libs/libusb as a dependency; enable scdaemon.
tofu Enable support for Trust on First use trust model; requires dev-db/sqlite.
tools Install extra tools (including gpgsplit and gpg-zip).
usb Build direct CCID access for scdaemon; requires dev-libs/libusb.
user-socket try a socket directory which is not removed by init manager at session end
wks-server Install the wks-server

gnupg-pkcs11-scd

proxy Build the gnupg-pkcs11-scd-prox

gpgme

common-lisp Install common-lisp files

hashcat

brain Enable the hashcat brain

heimdal

hdb-ldap Adds support for LDAP as a database backend
otp Adds support for one-time passwords
pkinit Adds support for PKINIT for the initial ticket

hmaccalc

fips Enable NSS FIPS mode and support only the FIPS-compliant functions

johntheripper

cuda Use nvidia cuda toolkit for speeding up cracking on capable devices
mozilla Support mozilla password cracking
opencl Enable opencl support for speeding up cracking on capable devices

kbfs

git Build the Git remote helper for storing repositories in Keybase

kstart

afs Enables afs support which means you can acquire an afs token and set PAGs. It's recommended to set this USE if you need authenticated access to an AFS cell for your daemon/app.

libb2

native-cflags Use CFLAGS as determined by configure script. These flags will enable all CPU specific features it find available, to further optimise the implementation. This discards any existing CFLAGS set in make.conf or similar.

libu2f-host

systemd Use user ACLs rather than plugdev group to give user access to the HIDRAW device.

mit-krb5

doc Creates and installs the API and implementation documentation. This is only useful if you want to develop software which depends on kerberos.
keyutils Enable for the keyring ccache using keyutils.
openldap Enable support for ldap as a database backend.
pkinit Enable pkinit support for the initial ticket.

ophcrack

tables Require the additional tables used to carry out cracking (app-crypt/ophcrack-tables)

ophcrack-tables

vistafree Installs the free Vista ophcrack tables
xpfast Installs the fast XP ophcrack tables
xpsmall Installs the small free XP ophcrack tables

p11-kit

asn1 Enable ASN.1 certificate support
trust Build the trust policy module

qca

botan Enable botan plugin
gcrypt Enable gcrypt plugin
gpg Enable GnuPG plugin
logger Enable logger plugin
nss Enable NSS plugin
pkcs11 Enable PKCS#11 plugin
sasl Enable SASL plugin
softstore Enable softstore plugin

seahorse

ldap Enable seahorse to manipulate GPG keys on a LDAP server.

tpm-emulator

mtm-emulator Build the MTM emulator

tpm-tools

pkcs11 Build Token data management utilities based on OpenCryptoki's (dev-libs/opencryptoki) PKCS#11 implementation.

veracrypt

asm Enable assembly for optimization

zulucrypt

gnome Enable support for the freedesktop.org Secret Service API via app-crypt/libsecret
kwallet Enable encrypted storage of passwords with kde-frameworks/kwallet
udev Whether udev will be consulted when deciding if a volume is system or not

app-dicts

aspell-be

classic Support classic spelling by default

gwaei

hunspell Enable app-text/hunspell spellchecking and morphological analysis
mecab Enable app-text/mecab support

myspell-pt

preao Use the pre ortographic agreement version of the dictionary

app-doc

clsync-docs

api Install doxygen generated API docs.

csound-manual

html Install HTML documentation

doxygen

clang support for sys-devel/clang assisted parsing
dot allow to create dot graphs using media-gfx/graphviz
doxysearch build doxyindexer and doxysearch.cgi

gnucash-docs

l10n_C English

kicad-doc

html Generate documentation in HTML format
pdf Generate documentation in PDF format

linuxfromscratch

htmlsingle Install all-on-one-page HTML version.

pms

binary Download pre-built files instead of building from sources
html Generate PMS as .html as well
twoside Enable two-sided layout suitable for printing

tldp-howto

html Install multi-chapter HTML docs
htmlsingle Install all-on-one-page HTML docs
pdf Install pdf docs
text Install plain-text docs

app-editors

bluefish

gtk2 Enable GTK2 instead of GTK3 even if GTK3 is available
gtk3 Enable GTK3 interface (default)
gucharmap Enable gucharmap dictionary plugin
python Enable Python integration for zen-coding plugin
spell Enable spell checking capabilities via enchant library

emacs

athena Enable the MIT Athena widget set (x11-libs/libXaw)
dynamic-loading Enable loading of dynamic libraries at runtime
games Support shared score files for games
gconf Use gnome-base/gconf to read the system font name
gfile Use gfile (dev-libs/glib) for file notification
gsettings Use gsettings (dev-libs/glib) to read the system font name
gtk2 Prefer version 2 of the GIMP Toolkit to version 3 (x11-libs/gtk+)
gtk3 Prefer version 3 of the GIMP Toolkit to version 2 (x11-libs/gtk+)
gzip-el Compress bundled Emacs Lisp source
imagemagick Use media-gfx/imagemagick for image processing
libxml2 Use dev-libs/libxml2 to parse XML instead of the internal Lisp implementations
mailutils Retrieve e-mail using net-mail/mailutils instead of the internal movemail substitute
source Install C source files and make them available for find-function
toolkit-scroll-bars Use the selected toolkit's scrollbars in preference to Emacs' own scrollbars
wide-int Prefer wide Emacs integers (typically 62-bit). This option has an effect only on architectures where "long" and "long long" types have different size.
xwidgets Enable use of GTK widgets in Emacs buffers (requires GTK3)

emacs-vcs

athena Enable the MIT Athena widget set (x11-libs/libXaw)
dynamic-loading Enable loading of dynamic libraries at runtime
games Support shared score files for games
gconf Use gnome-base/gconf to read the system font name
gfile Use gfile (dev-libs/glib) for file notification
gsettings Use gsettings (dev-libs/glib) to read the system font name
gtk2 Prefer version 2 of the GIMP Toolkit to version 3 (x11-libs/gtk+)
gzip-el Compress bundled Emacs Lisp source
imagemagick Use media-gfx/imagemagick for image processing
json Compile with native JSON support using dev-libs/jansson
libxml2 Use dev-libs/libxml2 to parse XML instead of the internal Lisp implementations
mailutils Retrieve e-mail using net-mail/mailutils instead of the internal movemail substitute
source Install C source files and make them available for find-function
threads Add elisp threading support
toolkit-scroll-bars Use the selected toolkit's scrollbars in preference to Emacs' own scrollbars
wide-int Prefer wide Emacs integers (typically 62-bit). This option has an effect only on architectures where "long" and "long long" types have different size.
xwidgets Enable use of GTK widgets in Emacs buffers (requires GTK3)

fe

sendmail Send mail after editor abend

gedit-plugins

charmap Insert special characters just by clicking on them
git Shows document changes related to git's HEAD
terminal Embed a terminal in the bottom pane

gvim

gtk3 Enable GTK+3 interface
netbeans Include netbeans external editor integration support
racket Enable support for Scheme using dev-scheme/racket

jasspa-microemacs

nanoemacs Build NanoEmacs instead of MicroEmacs

joe

xterm Enable full xterm clipboard support

latexila

latexmk Install dev-tex/latexmk (used by default for the build tools)
rubber Install dev-tex/rubber (can be used for the build tools)

leafpad

emacs Enable Emacs key theme

mousepad

gtk3 Use GTK+3 instead of GTK+2

nano

debug Enable debug messages and assert warnings. Note that these will all be sent straight to stderr rather than some logging facility.
justify Enable justify/unjustify functions for text formatting.
magic Add magic file support (sys-apps/file) to automatically detect appropriate syntax highlighting
minimal Disable all fancy features, including ones that otherwise have a dedicated USE flag (such as spelling).

ne

tinfo Link against libtinfo from sys-libs/ncurses

neovim

clipboard Enable clipboard support through a provider
nvimpager Install nvimpager symlink to less.sh macro
remote Enable support for remote options using nvr
tui Build the neovim unix tui

okteta

designer Build plugins for dev-qt/designer

qhexedit2

gui Install Qt5 hex editor

tea

aspell Enable spellchecking using app-text/aspell
hunspell Enable spellchecking using app-text/hunspell
qml Enable support for plugins using QML

vim

X Link console vim against X11 libraries to enable title and clipboard features in xterm
racket Enable support for Scheme using dev-scheme/racket
terminal Enable terminal emulation support
vim-pager Install vimpager and vimmanpager links

vis

tre more memory efficient regex search using dev-libs/tre

xemacs

athena Chooses the MIT Athena widget set
dnd Enables support for the x11-libs/dnd drag-n-drop library
eolconv Support detection and translation of newline conventions
pop Support POP for mail retrieval
xim Enable X11 XiM input method

zile

valgrind Enable usage of dev-util/valgrind in tests

app-emacs

anything

extensions Install optional extensions

auctex

preview-latex Use bundled preview-latex

bbdb

tex Install plain TeX support files
vm Add support for app-emacs/vm

calfw

howm Add support for the app-emacs/howm note-taking tool

company-mode

ropemacs Install backend for dev-python/ropemacs

emacs-common-gentoo

games Support shared score files for games

org-mode

contrib Install user-contributed files
odt-schema Install non-free schema files for OpenDocument Text exporter

remember

bbdb Include support for app-emacs/bbdb
planner Include support for app-emacs/planner

slime

xref Install xref.lisp cross-referencing tool

vm

bbdb Include support for app-emacs/bbdb

wanderlust

bbdb Include support for app-emacs/bbdb

wikipedia-mode

outline-magic Enable support for outline-mode extensions (app-emacs/outline-magic)

app-emulation

bochs

3dnow Enable support for emulating 3DNow! instructions (incomplete)
avx Enable support for emulating Advanced Vector Extensions (AVX)
debugger Enable debugger (slows down emulation)
gdb Enable support for the remote GDB stub
x86-64 Enable support for emulation of 64-bit CPUs

buildah

ostree Enables dependencies for handling of OSTree images.

containerd

apparmor Support for AppArmor
btrfs Support for BTRFS snapshot driver
cri Support for Kubernetes CRI

containers-storage

btrfs Enables dependencies for the "btrfs" graph driver, including necessary kernel flags.
device-mapper Enables dependencies for the "devicemapper" graph driver, including necessary kernel flags.
ostree Enables dependencies for handling of OSTree images.

cri-o

btrfs Enables dependencies for the "btrfs" graph driver, including necessary kernel flags.
device-mapper Enables dependencies for the "devicemapper" graph driver, including necessary kernel flags.
ostree Enables dependencies for handling of OSTree images.

crossover-bin

capi Enable ISDN support via CAPI
opencl Enable OpenCL support

docker

apparmor Enable AppArmor support.
aufs Enables dependencies for the "aufs" graph driver, including necessary kernel flags.
btrfs Enables dependencies for the "btrfs" graph driver, including necessary kernel flags.
container-init Makes the a staticly-linked init system tini available inside a container.
device-mapper Enables dependencies for the "devicemapper" graph driver, including necessary kernel flags.
overlay Enables dependencies for the "overlay" graph driver, including necessary kernel flags.
pkcs11 Enables pkcs-11 support.

docker-runc

ambient Enable support for ambient capability
apparmor Enable AppArmor support

dosemu

fluidsynth use media-sound/fluidsynth for MIDI emulation

e-uae

capslib Add CAPS library support
sdl-sound Use media-libs/sdl-sound for audio output

free42

alsa Adds support for Advanced Linux Sound Architecture

fuse

backend-X Use X11 rendering backend
backend-fbcon Use framebuffer rendering backend
backend-sdl Use SDL rendering backend
backend-svga Use svgalib rendering backend

fuse-utils

gcrypt Use dev-libs/libgcrypt for low-level crypto of some features, including logfiles.

ganeti

drbd Enable DRBD support
experimental Enable experimental patches. Warning! This will break RPC within major versions if the patches applied differ!
haskell-daemons Build haskell daemons instead of python
htools Enable htools support
kvm Enable KVM support
lxc Enable Linux Countainers support
monitoring Enable the ganeti monitoring daemon
multiple-users Enable support for running VMs as different users
rbd Enable rados block device support via sys-cluster/ceph
restricted-commands Enable restricted commands in the node daemon
xen Enable Xen support

hyperd

libvirt Enable support for KVM via libvirt
xen Enable support for the Xen Hypervisor

libcacard

passthrough Enable smartcard passthrough support via sys-apps/pcsc-lite

libguestfs

erlang Build Erlang bindings
fuse Enable image mount support via fuse
inspect-icons Use media-gfx/icoutilsfor acces icon file in image and inspect it
systemtap Use dev-util/systemtap to inspect VM via "probes" way

libspectrum

gcrypt Use dev-libs/libgcrypt for low-level crypto of some features, including logfiles.

libvirt

apparmor Enable AppArmor support
firewalld DBus interface to iptables/ebtables allowing for better runtime management of your firewall.
fuse Allow LXC to use sys-fs/fuse for mount points
glusterfs Enable GlusterFS support via sys-cluster/glusterfs
iscsi Allow using an iSCSI remote storage server as pool for disk image storage
libssh Use net-libs/libssh to communicate with remote libvirtd hosts, for example: qemu+libssh://server/system
libvirtd Builds the libvirtd daemon as well as the client utilities instead of just the client utilities
lvm Allow using the Logical Volume Manager (sys-fs/lvm2) as pool for disk image storage
lxc Support management of Linux Containers virtualisation (app-emulation/lxc)
macvtap Support for MAC-based TAP (macvlan/macvtap). For networking instead of the normal TUN/TAP. It has its advantages and disadvantages. macvtap support requires very new kernels and is currently evolving. Support for this is experimental at best.
nfs Allow using Network File System mounts as pool for disk image storage
numa Use NUMA for memory segmenting via sys-process/numactl and sys-process/numad
openvz Support management of OpenVZ virtualisation (openvz-sources)
parted Allow using real disk partitions as pool for disk image storage, using sys-block/parted to create, resize and delete them.
pcap Support auto learning IP addreses for routing
phyp Support IBM HMC / IVM hypervisor via PHYP protocol
qemu Support management of QEMU virtualisation (app-emulation/qemu)
rbd Enable rados block device support via sys-cluster/ceph
uml Support management of User Mode Linux virtualisation
vepa Virtual Ethernet Port Aggregator (VEPA) / 802.1Qbg support. Relies on macvtap support.
virt-network Enable virtual networking (NAT) support for guests. Includes all the dependencies for NATed network mode. Effectively any network setup that relies on libvirt to setup and configure network interfaces on your host. This can include bridged and routed networks ONLY if you are allowing libvirt to create and manage the underlying devices for you. In some cases this requires enabling the 'netcf' USE flag (currently unavailable).
virtualbox Support management of VirtualBox virtualisation (one of app-emulation/virtualbox or app-emulation/virtualbox-bin)
wireshark-plugins Build the net-analyzer/wireshark plugin for the Libvirt RPC protocol
xen Support management of Xen virtualisation (app-emulation/xen)
zfs Enable ZFS backend storage sys-fs/zfs

lxc

apparmor Enable AppArmor support
cgmanager Enable support for cgroup management using app-admin/cgmanager
templates Install old style templates through app-emulation/lxc-templates

lxd

daemon Build the system daemon, not just the client tool
dnsmasq Depend on dnsmasq to provide DHCP and DNS
tools Build and install optional tools

nemu

ovf Adds support for OVA/OVF import
savevm Adds support for QEMU savevm snapshots (experimental, QEMU must be patched)
vnc-client Adds support for external VNC client

open-vm-tools

caf Build Common Agent Framework
deploypkg Build deploypkg plugin
dnet Enable support for nicinfo
doc Generate API documentation
fuse Enable vmblock-fuse/vmhgfs-fuse
grabbitmqproxy Build grabbitmqproxy plugin
gtkmm Compile with Gtkmm and sigc++ (Recommended)
multimon Enable multimon (Requires X)
pic Force shared libraries to be built as PIC
resolutionkms Build the linux/unix resolutionkms module
vgauth Build vgauth
xml-security-c Build vgauth with xml-security-c instead of xmlsec1
xmlsec Build vgauth with xmlsec1 instead of xml-security-c

playonlinux

winbind Enables support for the winbind auth daemon

punes

cg Add support for Nvidia CG Toolkit

q4wine

ico Enable ico support via media-gfx/icoutils
iso Support unprivileged mounting of ISO9660 images via sys-fs/fuseiso
wineappdb Enable Wine AppDB browser support

qemu

accessibility Adds support for braille displays using brltty
aio Enables support for Linux's Async IO
alsa Enable alsa output for sound emulation
capstone Enable disassembly support with dev-libs/capstone
curl Support ISOs / -cdrom directives vis HTTP or HTTPS.
fdt Enables firmware device tree support
glusterfs Enables GlusterFS cluster fileystem via sys-cluster/glusterfs
gnutls Enable TLS support for the VNC console server. For 1.4 and newer this also enables WebSocket support. For 2.0 through 2.3 also enables disk quorum support.
gtk2 Use gtk-2 instead of gtk-3
iscsi Enable direct iSCSI support via net-libs/libiscsi instead of indirectly via the Linux block layer that sys-block/open-iscsi does.
jpeg Enable jpeg image support for the VNC console server
ncurses Enable the ncurses-based console
nfs Enable NFS support
numa Enable NUMA support
pin-upstream-blobs Pin the versions of BIOS firmware to the version included in the upstream release. This is needed to sanely support migration/suspend/resume/snapshotting/etc... of instances. When the blobs are different, random corruption/bugs/crashes/etc... may be observed.
png Enable png image support for the VNC console server
pulseaudio Enable pulseaudio output for sound emulation
rbd Enable rados block device backend support, see http://ceph.newdream.net/wiki/QEMU-RBD
sdl Enable the SDL-based console
sdl2 Use libsdl2 instead of libsdl
snappy Enable support for snappy compression
spice Enable Spice protocol support via app-emulation/spice
ssh Enable SSH based block device support via net-libs/libssh2
static Build the User and Software MMU (system) targets as well as tools as static binaries
static-user Build the User targets as static binaries
systemtap Enable SystemTAP/DTrace tracing
tci Enable the TCG Interpreter which can speed up or slowdown workloads depending on the host and guest CPUs being emulated. In the future it will be a runtime option but for now its compile time.
usb Enable USB passthrough via dev-libs/libusb
usbredir Use sys-apps/usbredir to redirect USB devices to another machine over TCP
vde Enable VDE-based networking
vhost-net Enable accelerated networking using vhost-net, see http://www.linux-kvm.org/page/VhostNet
virgl Enable experimental Virgil 3d (virtual software GPU)
virtfs Enable VirtFS via virtio-9p-pci / fsdev. See http://wiki.qemu.org/Documentation/9psetup
vte Enable terminal support (x11-libs/vte) in the GTK+ interface
xattr Add support for getting and setting POSIX extended attributes, through sys-apps/attr. Requisite for the virtfs backend.
xen Enables support for Xen backends
xfs Support xfsctl() notification and syncing for XFS backed virtual disks.

qt-virt-manager

smartcard Enable smartcard remoting using app-emulation/libcacard

rkt

actool Install the actool for ACI manipulation
rkt_stage1_coreos Download and use a prebuilt stage1.aci from CoreOS
rkt_stage1_fly Build stage1-fly.aci
rkt_stage1_host Assemble stage1.aci from host binaries
rkt_stage1_kvm This flag has been replaced by the rkt_stage1_kvm_* flags
rkt_stage1_kvm_lkvm Build stage1-kvm-lkvm.aci
rkt_stage1_kvm_qemu Build stage1-kvm-qemu.aci
rkt_stage1_src Build the stage1.aci from source

runc

ambient Enable support for ambient capabilities set (Requires Linux kernel 4.3 or later).
apparmor Enable AppArmor support.

runv

libvirt Enable support for KVM via libvirt
xen Enable support for the Xen Hypervisor

spice

lz4 Enable support for LZ4 compression using app-arch/lz4
smartcard Enable smartcard remoting using app-emulation/libcacard

spice-vdagent

consolekit Use sys-auth/consolekit to determine the master vdagentd in case of multiple running vdagentds (highly recommended)

uae

scsi Enable the uaescsi.device

vagrant

virtualbox Use VirtualBox provider.

vice

ethernet Enable ethernet emulation
fullscreen Enable the ability to run fullscreen
sdlsound Use media-libs/libsdl for sound support
vte Enable support for x11-libs/vte in the GTK+ interface

virt-manager

policykit Enables sys-auth/polkit authentication support, required when using app-emulation/libvirt with PolicyKit authentication
sasl Depend on the proper libraries needed to connect to SASL-enabled libvirtd instances (e.g. Kerberos-protected instances).

virt-viewer

spice Support connecting to SPICE-enabled virtual machines.
vnc Support connecting to VNC-enabled virtual machines.

virt-what

dmi Use sys-apps/dmidecode to read firmware data

virtualbox

headless Build without any graphic frontend
lvm Build VBoxVolInfo that needs devicemapper from sys-fs/lvm2.
pax_kernel Apply patch needed for pax enabled kernels.
sdk Enable building of SDK
udev Controls installation of special USB udev rules.
vboxwebsrv Build and install the VirtualBox webservice

virtualbox-bin

additions Install Guest System Tools ISO
chm Install kchmviewer binary to enable online help (in MS CHM format)
headless Install without any graphic frontend
rdesktop-vrdp Install the rdesktop client integration
sdk Enable building of SDK
vboxwebsrv Install the VirtualBox webservice

virtualbox-modules

pax_kernel Apply patch needed for pax enabled kernels

vkd3d

spirv-tools Enable SPIRV shader debugging support using dev-util/spirv-tools

vov

gprof build with profiling support

wine-any

capi Enable ISDN support via CAPI
custom-cflags Bypass strip-flags; use at your own peril
d3d9 Apply highly experimental patches for Gallium Nine support. This patch may break some applications.
dos Pull in games-emulation/dosbox to run DOS applications
ffmpeg Use media-video/ffmpeg to decode WMA formats
gecko Add support for the Gecko engine when using iexplore
gssapi Use GSSAPI (Kerberos SSP support)
gstreamer Use media-libs/gstreamer to provide DirectShow functionality;
mono Add support for .NET using Wine's Mono add-on
netapi Use libnetapi from net-fs/samba to support Windows networks in netapi32.dll
opencl Enable OpenCL support
osmesa Add support for OpenGL in bitmaps using libOSMesa
pcap Support packet capture software (e.g. wireshark)
perl Install helpers written in perl (winedump/winemaker)
pipelight Apply Wine-Staging patches for Pipelight/Silverlight support
prelink Run prelink on DLLs during build; For Gentoo hardened, do not disable if you do not know what this means as it can break things at runtime
realtime Pull in sys-auth/rtkit for low-latency pulseaudio support
run-exes Use Wine to open and run .EXE and .MSI files
samba Add support for NTLM auth. See: https://web.archive.org/web/20160108123008/http://wiki.winehq.org:80/NtlmAuthSetupGuide and https://web.archive.org/web/20150906013746/http://wiki.winehq.org/NtlmSigningAndSealing (these pages are not currently in the updated WineHQ Wiki).
sdl Add support for gamepad detection using SDL
staging Apply Wine-Staging patches for advanced feature support that haven't made it into upstream Wine yet
themes Support GTK+:3 window theming through Wine-Staging
udev Use virtual/libudev to provide plug and play support
vkd3d Use app-emulation/vkd3d to provide Direct3D 12 support
vulkan Enable Vulkan drivers

wine-d3d9

capi Enable ISDN support via CAPI
custom-cflags Bypass strip-flags; use at your own peril
d3d9 Apply highly experimental patches for Gallium Nine support. This patch may break some applications.
dos Pull in games-emulation/dosbox to run DOS applications
gecko Add support for the Gecko engine when using iexplore
gssapi Use GSSAPI (Kerberos SSP support)
gstreamer Use media-libs/gstreamer to provide DirectShow functionality;
mono Add support for .NET using Wine's Mono add-on
netapi Use libnetapi from net-fs/samba to support Windows networks in netapi32.dll
opencl Enable OpenCL support
osmesa Add support for OpenGL in bitmaps using libOSMesa
pcap Support packet capture software (e.g. wireshark)
perl Install helpers written in perl (winedump/winemaker)
prelink Run prelink on DLLs during build; For Gentoo hardened, do not disable if you do not know what this means as it can break things at runtime
realtime Pull in sys-auth/rtkit for low-latency pulseaudio support
run-exes Use Wine to open and run .EXE and .MSI files
samba Add support for NTLM auth. See: https://web.archive.org/web/20160108123008/http://wiki.winehq.org:80/NtlmAuthSetupGuide and https://web.archive.org/web/20150906013746/http://wiki.winehq.org/NtlmSigningAndSealing (these pages are not currently in the updated WineHQ Wiki).
sdl Add support for gamepad detection using SDL
udev Use virtual/libudev to provide plug and play support
vkd3d Use app-emulation/vkd3d to provide Direct3D 12 support
vulkan Enable Vulkan drivers

wine-staging

capi Enable ISDN support via CAPI
custom-cflags Bypass strip-flags; use at your own peril
dos Pull in games-emulation/dosbox to run DOS applications
ffmpeg Use media-video/ffmpeg to decode WMA formats
gecko Add support for the Gecko engine when using iexplore
gssapi Use GSSAPI (Kerberos SSP support)
gstreamer Use media-libs/gstreamer to provide DirectShow functionality;
mono Add support for .NET using Wine's Mono add-on
netapi Use libnetapi from net-fs/samba to support Windows networks in netapi32.dll
opencl Enable OpenCL support
osmesa Add support for OpenGL in bitmaps using libOSMesa
pcap Support packet capture software (e.g. wireshark)
perl Install helpers written in perl (winedump/winemaker)
pipelight Apply Wine-Staging patches for Pipelight/Silverlight support
prelink Run prelink on DLLs during build; For Gentoo hardened, do not disable if you do not know what this means as it can break things at runtime
realtime Pull in sys-auth/rtkit for low-latency pulseaudio support
run-exes Use Wine to open and run .EXE and .MSI files
samba Add support for NTLM auth. See: https://web.archive.org/web/20160108123008/http://wiki.winehq.org:80/NtlmAuthSetupGuide and https://web.archive.org/web/20150906013746/http://wiki.winehq.org/NtlmSigningAndSealing (these pages are not currently in the updated WineHQ Wiki).
sdl Add support for gamepad detection using SDL
staging Apply Wine-Staging patches for advanced feature support that haven't made it into upstream Wine yet
themes Support GTK+:3 window theming through Wine-Staging
udev Use virtual/libudev to provide plug and play support
vkd3d Use app-emulation/vkd3d to provide Direct3D 12 support
vulkan Enable Vulkan drivers

wine-vanilla

capi Enable ISDN support via CAPI
custom-cflags Bypass strip-flags; use at your own peril
dos Pull in games-emulation/dosbox to run DOS applications
gecko Add support for the Gecko engine when using iexplore
gssapi Use GSSAPI (Kerberos SSP support)
gstreamer Use media-libs/gstreamer to provide DirectShow functionality;
mono Add support for .NET using Wine's Mono add-on
netapi Use libnetapi from net-fs/samba to support Windows networks in netapi32.dll
opencl Enable OpenCL support
osmesa Add support for OpenGL in bitmaps using libOSMesa
pcap Support packet capture software (e.g. wireshark)
perl Install helpers written in perl (winedump/winemaker)
prelink Run prelink on DLLs during build; For Gentoo hardened, do not disable if you do not know what this means as it can break things at runtime
realtime Pull in sys-auth/rtkit for low-latency pulseaudio support
run-exes Use Wine to open and run .EXE and .MSI files
samba Add support for NTLM auth. See: https://web.archive.org/web/20160108123008/http://wiki.winehq.org:80/NtlmAuthSetupGuide and https://web.archive.org/web/20150906013746/http://wiki.winehq.org/NtlmSigningAndSealing (these pages are not currently in the updated WineHQ Wiki).
sdl Add support for gamepad detection using SDL
udev Use virtual/libudev to provide plug and play support
vkd3d Use app-emulation/vkd3d to provide Direct3D 12 support
vulkan Enable Vulkan drivers

winetricks

rar Pull in app-arch/unrar for extraction of rar-compressed game files

x48

readline Enables support for libreadline

xe-guest-utilities

xenstore Use xenstore binaries bundled by Citrix instead of building app-emulation/xen-tools

xen

efi Adds efi boot support, requires LDFLAG -melf_x86_64 for amd64
flask Enable the Flask XSM module from NSA

xen-tools

api Build the C libxenapi bindings
flask Enable the Flask XSM module from NSA
hvm Enable support for hardware based virtualization (VT-x,AMD-v)
ocaml Enable support for the ocaml language
ovmf Enable support to boot UEFI guest vm, needed by hvm
pam Enable pam support
pygrub Install the pygrub boot loader
qemu Enable IOEMU support via the use of qemu-dm
qemu-traditional Build the old qemu traditional device model (useful only if you cannot change to the new device model e.g. Windows VMs)
screen Enable support for running domain U console in an app-misc/screen session
system-qemu Using app-emulation/qemu instead of the bundled one
system-seabios Using sys-firmware/seabios instead of the bundled one

xtrs

ls-dos Install LS-DOS disk images for Model 4P

app-eselect

eselect-php

fpm Enable the FastCGI Process Manager SAPI

app-forensics

afflib

fuse Enable extra fuse thingies
qemu Enable qemu stuff
s3 Enable support for Amazon S3

aide

e2fs Enable support for checking file attributes on ext2/ext3/ext4 filesystems
prelink Bypass prelinking when calculating checksums

chkrootkit

cron Install cron script for weekly rootkit scans

libewf

bfio Enables libbfio for chaining file in file handling
fuse Enable fuse support for ewfmount
uuid Enable UUID support in the ewftools

openscap

gconf Build the gconf independant probes
nss Prefer NSS over libgcrypt as the crypto engine
rpm Compiles the RPM probes
sce Enables Script Check Engine (SCE) support
sql Build the sql independant probes

quickfuzz

archs support archive formats
codes support cource code formats
docs support document formats
imgs support image formats
media support media formats
net support networking formats
pki support PKI formats

sleuthkit

aff Enable extra aff formats
ewf Enable libewf support

app-i18n

anthy

canna-2ch Enable support for app-dicts/canna-2ch

canna

canuum Build canuum

fcitx

autostart Enable XDG-compatible autostart of Fcitx
enchant Enable Enchant backend (using app-text/enchant) for spelling hinting
gtk2 Install input method module for GTK+ 2
gtk3 Install input method module for GTK+ 3
opencc Enable OpenCC engine (using app-i18n/opencc) for converter between Simplified Chinese and Traditional Chinese
pango Enable support for x11-libs/pango
table Install table input methods for Simplified Chinese

fcitx-libpinyin

dictionary-manager Install dictionary manager

fcitx-rime

configuration_tool Install configuration tool

fcitx-unikey

macro-editor Install macro editor

freewnn

uum Build uum

ibus

emoji Enable support for Emoji
gconf Enable support for gnome-base/gconf
gtk2 Enable support for x11-libs/gtk+:2
unicode Enable support for Unicode choice

ibus-chewing

gconf Enable support for gnome-base/gconf

ibus-handwrite

zinnia Enable support for app-i18n/zinnia

ibus-libpinyin

boost Compile against dev-libs/boost libraries
opencc Enable support for app-i18n/opencc

ibus-m17n

gtk2 Build with x11-libs/gtk+:2 instead of x11-libs/gtk+:3

ibus-pinyin

boost Enable support for dev-libs/boost

ibus-unikey

gtk2 Enable support for x11-libs/gtk+:2

im-chooser

gtk2 Build with x11-libs/gtk+:2 instead of x11-libs/gtk+:3
xfce Enable support for XFCE panel

imsettings

gconf Enable support for gnome-base/gconf
gtk2 Build with x11-libs/gtk+:2 instead of x11-libs/gtk+:3
xfconf Enable support for xfce-base/xfconf

mozc

fcitx4 Enable support for app-i18n/fcitx 4
gui Install graphical user interface tool (mozc_tool)
handwriting-tegaki Use handwriting recognition model from app-i18n/tegaki-zinnia-japanese
handwriting-tomoe Use handwriting recognition model from app-i18n/zinnia-tomoe
ibus Enable support for app-i18n/ibus
renderer Enable native candidate window

pyzy

boost Enable support for dev-libs/boost
doc Generate API documentation
opencc Enable support for app-i18n/opencc

rime-data

extra Install extra packages

scim

gtk3 Enable support for x11-libs/gtk+:3

scim-anthy

gtk3 Enable support for x11-libs/gtk+:3
kasumi Use Anthy dictionary maintenance tool (app-dicts/kasumi)

scim-sunpinyin

gtk3 Enable support for x11-libs/gtk+:3

tomoe

hyperestraier Enable support for app-text/hyperestraier

translate-shell

tts Enable text-to-speech support

uim

anthy Enable support for app-i18n/anthy
eb Enable support for dev-libs/eb
gtk2 Enable support for x11-libs/gtk+:2
skk Enable support for app-i18n/skk-jisyo

app-laptop

hdapsd

libconfig Require dev-libs/libconfig to allow the daemon to read a configuration file at startup

ibam

gkrellm Enable building of app-admin/gkrellm module

pbbuttonsd

ibam Enable support for Intelligent Battery Monitoring
macbook Enable support for the Macbook and Macbook Pro

thinkfan

atasmart include libatasmart support to get disc temperature

tp_smapi

hdaps Install a compatible HDAPS module

app-leechcraft

lc-azoth

acetamide Build Acetamide, the IRC protocol support
adiumstyles Build support for Adium styles
astrality Build Astrality, support for protocols provided by Telepathy
autoidler Build support for automatic status changing according to user idle time
autopaste Build Autopaste for pasting long texts to pastebins
birthdaynotifier Build Birthday Notifier for you to not forget about birthdays of your contacts.
chathistory Build ChatHistory which stories chat history
depester Build Depester which enables to ignore MUC participants
embedmedia Build EmbedMedia for embedding flash videos and images directly into chat windows
herbicide Build Herbicide, a basic antispam plugin
hili Build HiLi which allows to customize highlight settings in MUCs
isterique Build Isterique plugin for neutralizing excessive caps lock usage
juick Build plugin for the Juick.com microblogging service
keeso Build plugin for changing text into SoMEtHInG lIKe THiS
lastseen Build plugin for client-side recording of the last online/available time
media Enable media calls
metacontacts Build plugin for metacontacts support
murm Build Murm, the VKontakte messaging support via their native API (instead of XMPP)
nativeemoticons Build support for native Azoth's emoticons packs
otroid Build OTRoid, plugin for the Off-the-Record deniable encryption system
sarin Build Sarin, Tox protocol support module. Please add mva overlay to use net-libs/tox
shx Build shell command executor plugin
standardstyles Build support for standard Azoth styles engine
vader Bulid Vader, the MRIM (Mail.Ru Agent) protocol support plugin
velvetbird Build support for protocols provided by libpurple
woodpecker Build Woodpecker, the Twitter client plugin
xtazy Build Xtazy for publishing currently playing tune

lc-blasq

deathnote Support LiveJournal FotoBilder service
rappor Support VKontakte service
spegnersi Support Flickr service
vangog Support Picasa service

lc-blogique

hestia Allows one to keep a local blog
metida Support for the LiveJournal blogging platform

lc-core

qwt Support for QML plotting item through x11-libs/qwt

lc-gmailnotifier

notify Pull in a plugin to show notifications from GMail Notiifer
quark Pull in a plugin to show GMail Notifier's quark

lc-lmp

fradj Build FrAdj, the equalizer effect module
graffiti Build media tags editor plugin
mp3tunes Build plugin for supporting the mp3tunes.com music locker service
mpris Enable MPRIS support
potorchu Enable the projectM-based visualization effects module for LMP

lc-monocle

fb2 Enable support for FictionBook format
mobi Enable support for MOBI format

lc-musiczombie

acoustid Use media-libs/chromaprint for acoustic fingerprinting

lc-netstoremanager

dropbox Build Dropbox storage backend
googledrive Build Google Drive storage backend

lc-poshuku

autosearch Provide automatic search suggestions for Poshuku.
cleanweb Build CleanWeb for ad blocking compatible with Firefox's AdBlock+.
dcac Build color inverter module providing a night mode.
fatape Build FatApe, GreaseMonkey userscripts support layer.
filescheme Build FileScheme for accessing local URLs.
foc Build FOC for Flash-on-Click functionality.
fua Build FUA for faking user agents for different hosts.
keywords Build Keywords for adjusting search shortcuts.
onlinebookmarks Build OnlineBookmarks for syncing bookmarks with social bookmarking services like Read It Later.
qrd Build module for displaying the QR code of a web page.
speeddial Build SpeedDial module.
webengine Build WebEngine- (that is, Chromium-)based rendering backend.

lc-secman

exposecontents Build the GUI for viewing the stored data.

leechcraft-meta

de Install components, that allow using Leechcraft as Desktop Environment

app-metrics

collectd

contrib Install user-contributed files in the doc directory
filecaps When set collectd daemon will have set required capabilities to run most plugins even if run as unprivileged user
java Must be set (workaround for java-pkg-opt-2 eclass limitation) when you want java or genericjmx plugin
udev Enable optional udev usage in disk plugin; Required for smart plugin
xfs Enable optional capability to filter on XFS file system in df plugin; Requires XFS headers from sys-fs/xfsprogs

app-misc

anki

recording Enable support for audio recording
sound Enable support for adding sound to cards

binwalk

graph Enable support for generating entropy graphs

blink1

mini-tool Build and install command-line mini-tool blink1-mini-tool (normally used for embedded devices)
server Build and install REST API server (currently hard-coded to TCP port 8080)
tool Build and install command-line tool blink1-tool

byobu

screen Use app-misc/screen as the default backend

ca-certificates

cacert Include root certificates from CAcert (http://www.cacert.org/) and Software in the Public Interest (http://www.spi-inc.org/)
insecure_certs Install certificates which are known to be untrustworthy.

carbon-c-relay

lz4 add support for LZ4 compressed transport
oniguruma use dev-libs/oniguruma as regex implementation
pcre2 use dev-libs/libpcre2 as regex implementation
snappy add support for Snappy compressed transport

ddccontrol

pci enable direct PCI memory access (the setuid ddcpci util)

ddcutil

drm Use x11-libs/libdrm for more verbose diagnostics.
usb-monitor Adds support for monitors attached via USB.
user-permissions Adds a udev rules to allow non-root users in the i2c group to access the /dev/i2c-* devices. If usb-monitor is selected, users will need to be added to the video group to access the USB monitor. Otherwise, only root will be able to use ddcutil.

digitemp

ds2490 Build support for the ds2490 sensor
ds9097 Build support for the ds9097 sensor
ds9097u Build support for the ds9097u sensor

elasticsearch

x-pack Enable additional features (may need a license)

emelfm2

ansi Add support for ANSI escape sequences
gtk3 Use x11-libs/gtk+:3 instead of x11-libs/gtk+:2

freemind

groovy Build plugin for scripting via Groovy
latex Build plugin for inserting mathematical formulas in LaTeX syntax
pdf Build plugin for exporting mindmaps to SVG and PDF
svg Build plugin for exporting mindmaps to SVG and PDF

g810-led

hidapi Use dev-libs/hidapi instead of virtual/libusb for talking to the device (advertised to be faster)

gcstar

stats Enable statistics reporting
tellico Enable support for kde-misc/tellico files

geoclue

geonames Install geonames.org provider
gsmloc Install GSM location provider
gtk Install gtk-based geoclue-test-gui
hostip Install hostip.info provder
manual Install manual provider
modemmanager Enable geolocation through 3G or GPS enabled hardware through net-misc/modemmanager.
nominatim Install openstreetmap.org provider
plazes Install plazes.com provider
skyhook Install skyhookwireless.com provider
yahoo-geo Install Yahoo geolocation provider
zeroconf Enable retrieval of GPS location from Android devices with https://wiki.gnome.org/Apps/GeoclueShare

gourmet

i18n Enable support for i18n through elib.intl
ipython Enable support for the interactive Python console plugin
pdf Enable export to PDF
print Enable pretty Python printing
spell Enable support for the spell check plugin
web Enable support for the web import plugin

gramps

geo Enable rendering of geographical data using sci-geosciences/osm-gps-map
rcs Adds support for family tree archives via dev-vcs/rcs
reports All external software that is needed for graphical reports will be installed

graphlcd-base

g15 Add support for app-misc/g15daemon driver (e.g. Logitech G15 Keybord)

irtrans-irserver

mono Enable mono support

jq

oniguruma Use dev-libs/oniguruma for regular expression support

kryoflux-dtc

demos Install example floppy game files.
fast-firmware Install fast firmware instead of slow firmware.
gui Install the Kryoflux GUI

lcd4linux

apm Enable the APM plugin.
asterisk Enable the Asterisk plugin.
button_exec Enable the Button plugin, to execute something on keypress.
cpuinfo Enable the cpuinfo plugin.
dbus Enable the dbus plugin.
diskstats Enable the diskstats plugin.
dmalloc Enable dmalloc for debugging.
dvb Enable support for the DVB plugin.
event Enable the event plugin.
exec Enable the exec plugin, to read output from external programs.
fifo Enable the FIFO (First-In, First-Out) plugin.
file Enable the file plugin, to read from input from files.
gps Enable the gps plugin, for reading gps coordinates.
hddtemp Enable the hddtemp plugin, to read from the hddtemp daemon.
huawei Enable the huawei plugin, to read from a huawei device.
i2c_sensors Enable the i2c_sensors plugin, to read sensor data.
iconv Enable the iconv plugin, to convert between encodings.
isdn Enable the isdn plugin, to get information about ISDN.
kvv Enable the kvv plugin, to get realtime train schedule from the Karlsruher Verkehrsverbund.
loadavg Enable the loadavg plugin, to get stats load
meminfo Enable the meminfo plugin, to get memory statistics.
mpd Enable the mpd plugin, to read from the Music Player Daemon.
mpris_dbus Enable the mpris plugin, to read data via dbus for mpris.
mysql Enable the mysql plugin, to get mysql database information.
netdev Enable the netdev plugin, to get interface statistics.
netinfo Enable the netinfo plugin, to get more interface statistic.
outb Enable raw i/o access.
pop3 Enable the pop3 plugin, to get notified about new mails.
proc_stat Enable the proc_stat plugin, to read data from the proc file system.
python Enable support for dev-lang/python and enable the python plugin, to execute own python scripts.
qnaplog Enable the qnaplog plugin, to read a log from a QNAP device.
raspi Enable the raspi plugin, to read sensor data from a Raspberry Pi.
sample Enable the sample plugin.
statfs Enable the statfs plugin, to get statistics about the file system.
uname Enable the uname plugin, to get the output of uname.
uptime Enable the uptime plugin.
w1retap Enable the w1retap plugin.
wireless Enable the wireless plugin, to get wireless statistics.

lcdproc

ethlcd Enable support for ethlcd in the hd44780 driver.
extra-charmaps Enable extra language specific charmaps.
freetype Enable support for media-libs/freetype in the glcd driver.
ftdi Enable support for dev-embedded/libftdi in the glcd,hd44780,i2500vfd,lis and ula200 driver.
hid Enable support for dev-libs/libhid in the cfontz,cfontzpacket,cwlnx,glcd,lb216,mdm166a,mtc_s16209x and noritakevfd driver.
irman Enable support for media-libs/libirman in the irman driver.
menu Enable menu support in the lcdproc client.
nfs Display NFS filesystem stats in the lcdproc client.
png Enable support for media-libs/libpng in the glcd driver.
samba Display SMBFS filesystem stats in the lcdproc client.
seamless-hbars Don't produce any gaps in horizontal bar graphs, if hardware supports it.
test-menu Enable test menu support for the lcdproc server.

lirc

audio Support using an audio device connected to an IR receiver
devinput Support the devinput input device
ftdi Support FTDI devices
gtk Include GTK support which enables the use of lirc-setup
inputlirc Add a dependency on app-misc/inputlircd
uinput Enable support for uinput

mc

edit Compile and install the mcedit application
mclib Compile and install the libmc.so shared library
sftp Add support for sftp (uses net-libs/libssh2 for it).
slang Use sys-libs/slang instead of sys-libs/ncurses.
xdg Toggles mc's config dir location. Enable for $XDG_CONFIG_HOME/mc, disable for $HOME/.mc

mosquitto

bridge Enable bridge support in the MQTT broker.
persistence Store messages and subscriptions to a file.
srv Include SRV lookup support.
websockets Support the WebSocket protocol.

muttprint

doc Builds documentation

neofetch

X Enable support for detecting DEs, WMs, screen resolutions, and showing images from an X terminal

nnn

fish-completion Enable fish completion support

note

general Add support for ascii flatfile backend
text Add support for text backend

openastro

jpeg Enable exporting Astrological Charts to jpeg
png Enable exporting Astrological Charts to png

pax-utils

python Install a more powerful/faster version of lddtree

recoll

camelcase Enable indexing for camelCase sentences and words
inotify Use the Linux Kernel notification subsystem for monitoring file alterations in realtime
session Stop monitoring file alterations when X11 session terminates

rlwrap

debug Enable debug

screen

multiuser Enable multiuser support (by setting correct permissions)
nethack Express error messages in nethack style
utmp Include utmp support

screenfetch

X Use the media-gfx/scrot package to take screenshots

skim

tmux Install sk-tmux script to run skim in a tmux pane
vim Install vim plugin for skim

sphinx

id64 use 64-bit document and word IDs
mariadb Add mariadb database support
re2 use the dev-libs/re2 regular expression library
stemmer Enable language stemming support

task

sync Enable "task sync" support

tmux

utempter Include libutempter support

towitoko

moneyplex Makes libtowitoko work for the moneyplex home banking software

tracker

cue Enable cue sheet parsing
firefox-bookmarks Install bookmark data miner plugin for www-client/firefox and www-client/firefox-bin
gsf Enable gnome-extra/libgsf based data extractor and for ODT.
iptc Enable extraction of IPTC data from pictures
iso Enable extraction of metadata from ISO disk images
miner-fs Enable tracker-miner-fs (required for filesystem indexing)
nautilus Enable tracker to integrate with gnome-base/nautilus by providing entries in its context menu
playlist Add support for playlists
stemmer Add word stemming via dev-libs/snowball-stemmer.
thunderbird Install email data miner plugin for mail-client/thunderbird and mail-client/thunderbird-bin
xps Add support for XPS file format through app-text/libgxps.

unfoo

minimal Do not install all support archive binaries

vcontrold

man Build the manpages
vclient Build the vclient helper program to talk to vcontrold
vsim Build the vsim helper program (simulates the heating's answers, for development and debugging)

vifm

X Add support for X11
developer Enable features of interest to developers
extended-keys Support for extended keys (arrows, home etc)
gtk Use gtk+ to determine mimetypes
magic Use libmagic to determine mimetypes
vim Install the vifm vim plugin and vim-compatible documentation
vim-syntax Pulls in related vim syntax scripts

worker

avfs Enable support for sys-fs/avfs
magic Add magic file support from sys-apps/file to automatically detect file types

workrave

mate Add support for MATE panel
xfce Add support for XFCE panel

zygrib

maps Installs additional GSHHS maps for high resolution coastline data and cities

app-mobilephone

gammu

bluetooth Enables bluetooth support
curl Enables curl support
irda Enables infrared support
mysql Use mysql for data storage
nls Enable native language support
odbc Use ODBC as DB connector
postgres Use PostgreSQL for data storage
usb Enable USB suport

gnokii

ical Enable support for dev-libs/libical
irda Enable infrared support
pcsc-lite Enable smartcard support with sys-apps/pcsc-lite
sms Enable SMS support (build smsd)

smstools

stats Enable statistic reporting

app-office

abiword

collab Enable collaborative editing plugin
goffice Enable goffice plugin
grammar Enable grammar checking via dev-libs/link-grammar
map Enable world map support through media-libs/libchamplain
math Enable support for x11-libs/gtkmathview
ots Enable Text Summarizer plugin
plugins Enable plugins build (see http://www.abisource.com/wiki/PluginMatrix for more information). If your file cannot be opened due lack of support, try enabling this.
redland Enables support redland and raptor libs.
thesaurus Enable thesaurus support
wordperfect Enable wordperfect file support via app-text/libwpd

calligra

activities Enable kactivities support
gemini Enable tablet and 2:1 devices support
import-filter Enable support for various import filter file formats like WordPerfect, Visio and Apple Keynote
lcms Build colorengine plugins using media-libs/lcms
okular Enable bindings for kde-apps/okular
phonon Build stage/eventplugins and videoshape plugin using media-libs/phonon
pim Enable support for KDE PIM resources integration
spacenav Enable support for the 3Dconnexion spacenav input device via dev-libs/libspnav

glabels

barcode Enable barcode support through external libraries.

gnucash

aqbanking Connect to some internet banks via AqBanking
chipcard Enable support for chipcard reading and processing.
gui Enable graphic interface (needs net-libs/webkit-gtk:4 and x11-libs/gtk+:3)
quotes Enable Online Stock Quote retrieval
register2 Use the new register (Experimental)

gnumeric

libgda Enable database support through gnome-extra/libgda.
perl Enable perl plugin loader.
python Enable python plugin loader.

kexi

experimental Enable features deemed experimental by upstream
marble Enable displaying of maps using kde-apps/marble
mdb Enable support for Microsoft Access database
webkit Enable web form designer widget using dev-qt/qtwebkit

kmymoney

activities Enable kde-frameworks/kactivities integration
addressbook Enable kde-apps/akonadi contact integration
hbci Enable HBCI support using net-libs/aqbanking
holidays Enable kde-frameworks/kholidays integration
quotes Enable Online Stock Quote retrieval
weboob Enable import of online banking transactions extracted by www-client/weboob

kraft

pim Enable support for KDE PIM resources integration

libreoffice

coinmp Use sci-libs/coinor-mp as alternative solver
googledrive Enable support for remote files on Google Drive
gtk2 Enable legacy gtk2 frontend
odk Build the Office Development Kit
pdfimport Enable PDF import via the Poppler library
vlc Use media-video/vlc for video embedding

libreoffice-l10n

offlinehelp Install help files locally instead of using the LibreOffice Wiki

lyx

aspell Add support for aspell spellchecking
dia Add support for diagrams (app-office/dia)
docbook Add support for docbook export
dot Add support for DOT import (media-gfx/graphviz)
enchant Add support for enchant spellchecking wrapper (both aspell and hunspell can be used by LyX).
gnumeric Add support for importing Gnumeric/OpenOffice/MS Excel spreadsheets into LyX.
html Add support for HTML import
hunspell Add support for spellchecking based on hunspell and reuse system-wide OpenOffice dictionaries. This also enable thesaurus dictionaries not accessible via aspell.
monolithic-build This should speed up compilation significantly when you have enough RAM (> 600 MB)
rcs Add support for revision control via dev-vcs/rcs
rtf Add support for RTF import/export packages

magicpoint

contrib Install additional contributed scripts

orage

clock-panel-plugin Build the clock plugin for the XFCE panel

scribus

boost Enable support for Boost based enhancement
hunspell Enable support for spell checking with app-text/hunspell
minimal Don't install headers (only required for e.g. plug-in developers)
osg 3D redering via dev-games/openscenegraph
scripts Install the scripts
templates Document tamplates
tk Install tk based scripts e.g. FontSample.py

skrooge

activities Enable kactivities support
designer Build plugins for dev-qt/designer

texmacs

netpbm Add support for media-libs/netpbm

texstudio

video Use phonon for video embedding

wps-office

sharedfonts Install WPS fonts available system wide

app-pda

barry

boost Enable boost support
gui Install the GUI backup tool

gtkpod

clutter Enable clutter support for displaying coverart

app-portage

conf-update

colordiff Use colors when displaying diffs (app-misc/colordiff)
libressl Enable SSL connections and crypto functions using dev-libs/libressl

eix

debug Build with upstream's CXXFLAGS/LDFLAGS for debugging support; not recommended for normal use.
doc Create description of the eix cache file additionally in html format
sqlite Compile in support for portage's sqlite backend; to actually use it you need additional configuration of portage and eix

g-sorcery

bson Support BSON file format for package DB

gemato

blake2 Install dependencies needed for BLAKE2 hash functions
gpg Install dependencies needed for OpenPGP signature verification support
sha3 Install dependencies needed for SHA3 hash functions
tools Install additional utilities (benchmarks, hash testing tools, fast Manifest generators) to /usr/share/gemato.

grs

server Install all the tools building systems

layman

bazaar Support dev-vcs/bzr based overlays
cvs Support dev-vcs/cvs based overlays
darcs Support dev-vcs/darcs based overlays
g-sorcery Support app-portage/g-sorcery based overlays
git Support dev-vcs/git based overlays
gpg Support app-crypt/gnupg signed overlays lists and manifests
mercurial Support dev-vcs/mercurial based overlays
squashfs Support mounting squashfs image overlays locally read-only
subversion Support dev-vcs/subversion based overlays
sync-plugin-portage Install the sys-apps/portage sync module

pfl

network-cron Adds a cron job which does a weekly submit of the package database

tatt

templates Install template scripts to be used with tatt

app-shells

autojump

ipython Add support for dev-python/ipython

bash

bashlogger Log ALL commands typed into bash; should ONLY be used in restricted environments such as honeypots
mem-scramble Build with custom malloc/free overwriting allocated/freed memory
net Enable /dev/tcp/host/port redirection
plugins Add support for loading builtins at runtime via 'enable'

dash

vanilla Support echo -n, and enable echo -e all the time (unsupported)

pdsh

rsh This allows the use of rsh (remote shell) and rcp (remote copy) for authoring websites. sftp is a much more secure protocol and is preferred.

shish

diet Use dev-libs/dietlibc

app-text

asciidoc

highlight Enable source code highlighting

atril

caja Enable property page extension in mate-base/caja
dvi Enable build-in DVI viewer
epub Enable build-in DVI viewer using net-libs/webkit-gtk
t1lib Enable the Type-1 fonts for the build-in DVI viewer (media-libs/t1lib)
xps Enable XPS viewer using app-text/libgxps

blogc

git Build blogc-git-receiver tool
httpd Build blogc-runserver tool
make Build blogc-make tool

cb2bib

webengine Use dev-qt/qtwebengine instead of dev-qt/qtwebkit

coolreader

wxwidgets Use x11-libs/wxGTK instead of Qt5

crm114

mew Add support for using the mewdecode mime decoder (app-emacs/mew)
mimencode Add support for using the mimencode mime (net-mail/metamail)
normalizemime Add support for using the normalizemime (mail-filter/normalizemime)

dbacl

interactive Enable the interactive mailinspect ability

dblatex

inkscape Use inkscape to convert SVG. Disable to use gnome-base/librsvg instead.

dictd

judy Build Judy-based (dev-libs/judy) plugin implementing fast "exact" and especially "lev" strategies
minimal Don't build server but dict client, dictzip and dictfmt only.

docbook-sgml-utils

jadetex Add support for app-text/jadetex (for processing tex files produced by the TeX backend of Jade)

docbook-xsl-ns-stylesheets

ruby Install the Ruby-based dbtoepub script; requires an interpreter compatible with app-eselect/eselect-ruby.

docbook-xsl-stylesheets

ruby Install the Ruby-based dbtoepub script; requires an interpreter compatible with app-eselect/eselect-ruby.

ebook-tools

lit2epub Install lit2epub script

editorconfig-core-c

cli Install command line interface.

enchant

aspell Adds support for app-text/aspell spell checker
hunspell Adds support for app-text/hunspell spell checker

evince

dvi Enable the built-in DVI viewer
nautilus Enable property page extension in gnome-base/nautilus
postscript Enable support for PostScript and Adobe Illustrator documents with app-text/libspectre
t1lib Enable the Type-1 fonts for the built-in DVI viewer (media-libs/t1lib)
xps Enable XPS viewer using app-text/libgxps

getxbook

ocr Use app-text/tesseract for optical character recognition

ghostscript-gpl

unicode Add support for unicode passwords via net-dns/libidn

glark

zip Support for ZIP files using dev-ruby/rubyzip

groonga

abort Enable query abortion
benchmark Build benchmark programs
dynamic-malloc-change Allow dynamic memory allocation change for testing
exact-alloc-count Atomic counting for memory alloc count
fmalloc Make memory allocation failed in specified condition for debug
futex Use futex
libevent Enable dev-libs/libevent used for suggestion
mecab Use app-text/mecab for morphological analysis
msgpack Enable dev-libs/msgpack used for suggestion
nfkc Use nfkc based utf8 normalization
sphinx Enable document generation by app-misc/sphinx
uyield Build for detecting race conditions
zeromq Enable net-libs/zeromq used for suggestion
zstd Utilize app-arch/zstd for Zstandard compression

gtranslator

gnome-dictionary Enable plugin for dictionary lookups using app-dicts/gnome-dictionary.
gucharmap Enable plugin for unicode symbols selection using gnome-extra/gucharmap.

hyperestraier

mecab Enable app-text/mecab support for Estraier

kbibtex

webengine Use dev-qt/qtwebengine for HTML previews
webkit Use dev-qt/qtwebkit for HTML previews
zotero Enable support for synchronisation with zotero.org web service

lcdf-typetools

kpathsea Enable integration with kpathsea search library (TeX related)

libebook

tools Build file conversion tools

libmwaw

tools Build file conversion tools

libqxp

tools Build file conversion tools

libstaroffice

tools Build conversion tools
zlib Enable support for compressed data

libwpd

tools Build file conversion tools

libwps

tools Build file conversion tools

mathtex

png Generate png images by default instead of gif

msort

heap Use heap instead of alloca()
icu Use dev-libs/icu instead of dev-libs/libutf8proc.
libuninum Use dev-libs/libuninum for conversion.

mupdf

openssl Use dev-libs/openssl crypto backend

pandoc

embed_data_files Embed data files in binary for relocatable executable.
http-conduit Enable downloading of resources over https.
https Enable support for downloading of resources over https.
make-pandoc-man-pages Build program to regenerate pandoc man pages from README.
network-uri Get Network.URI from the network-uri package.
trypandoc Build trypandoc cgi executable.
weigh-pandoc Build weigh-pandoc to measure memory usage.

pastebinit

crypt Install pbputs for gpg-encrypted pastes

pdfgrep

unac Removing accents and ligatures before search

pelican

markdown Markdown support

podofo

boost Add support for boost
tools Build and install commandline tools.

poppler

nss Enable signatures handling with dev-libs/nss
utils Install command-line PDF converters and various utilities.

qpdf

perl Install fix-qdf tool (for reverting PDF edits) written in perl

qpdfview

fitz Use experimental fitz rendering, provided by app-text/mupdf, instead of poppler
synctex Add support for searching TeX sources

sdcv

darkterm Improve readability of color output on terminals with dark background.

sgmltools-lite

jadetex Add support for app-text/jadetex (for processing tex files produced by the TeX backend of Jade)

stardict

advertisement Enable stardict advertisements plugin
cal Enable calendar support using cal program
dictdotcn Enable dict.cn network plugin (for Chinese language)
espeak Enable text to speech synthesizer plugin using app-accessibility/espeak engine
flite Enable text to speech synthesizer plugin using app-accessibility/flite engine
fortune Enable plugin to read fortune messages using games-misc/fortune-mod. You may consider installing games-misc/fortune-mod-all to get all fortune messages.
gucharmap Enable plugin for unicode symbols description using gnome-extra/gucharmap
htmlparse Enable plugin to parse dictionaries with html content
info Enable plugin to read info pages
man Enable plugin to read manual pages
powerwordparse Enable plugin to parse powerword dictionaries
pronounce Install WyabdcRealPeopleTTS package (it is just many .wav files) to make StarDict pronounce English words
qqwry Enable QQWry plugin, which provides information (in Chinese language) about geographical positions, owner, etc. for IP addresses
tools Build and install dictionary management tools and converters from various dictionary formats
updateinfo Enable plugin to check for stardict updates
wikiparse Enable plugin to parse dictionaries in wikimedia format
wordnet Enable wordnet plugin to find similar English words using lexical database
xdxfparse Enable plugin to parse dictionaries in xdxf (XML Dictionary eXchange Format)
youdaodict Enable youdao.com network plugin (for Chinese language)

sword

clucene Use dev-cpp/clucene for lucene search support

tesseract

math Enable support for recognition of equations.
opencl Enable opencl support for speedup using GPU computation.
osd Enable support orientation and script detection.
scrollview Install viewer to debug recognition (ScrollView).
training Install training applications to add support for new languages.

texlive

context Add support for the ConTeXt format (dev-texlive/texlive-context)
detex Add support for dev-tex/detex, a filter program that removes the LaTeX (or TeX) control sequences
dvi2tty Add support for dev-tex/dvi2tty to preview dvi-files on text-only devices
epspdf Add support for app-text/epspdf, a tool for converting [e]ps files to pdf
extra Add support for extra TeXLive packages
games Add typesetting support for games (chess, etc.) (dev-texlive/texlive-games)
graphics Add support for several graphics packages (pgf, tikz,...)
humanities Add LaTeX support for the humanities (dev-texlive/texlive-humanities)
jadetex Add support for app-text/jadetex (for processing tex files produced by the TeX backend of Jade)
luatex Add extra support for luatex
metapost Add support for metapost: A tool for creating graphics in scalable PostScript
music Add support for music typesetting (dev-texlive/texlive-music)
pdfannotextractor Add dev-tex/pdfannotextractor support, for extracting annotations from PDF files
pstricks Add pstricks packages (dev-texlive/texlive-pstricks)
publishers Add support for publishers (dev-texlive/texlive-publishers)
science Add typesetting support for natural and computer sciences (dev-texlive/texlive-mathscience)
tex4ht Add support for dev-tex/tex4ht (for converting (La)TeX to (X)HTML, XML and OO.org)
texi2html Add support for app-text/texi2html which converts texi files to HTML
xetex Add support for XeTeX macros (dev-texlive/texlive-xetex)
xindy Add support for app-text/xindy, a flexible indexing system

texlive-core

luajittex Add support for LuaJitTeX: LuaTeX based on LuaJIT which is usually faster.
xetex Add support for XeTeX: a TeX system with Unicode and modern font technologies.

wdiff

experimental Build experimental utilities (mdiff, unify, wdiff2)

webgen

builder Enable programmatic HTML/XML generation
highlight Enable syntax highlighting for certain plugins
markdown Markdown support

wklej

vim Install the vim plugin allowing to paste through ':Wklej'.

writerperfect

abiword Add support for abiword format using app-text/libabw
ebook Add support for various ebook formats using app-text/libebook
freehand Add support for freehand format using media-libs/libfreehand
gsf Add support for structured files using gnome-extra/libgsf
keynote Add support for keynote format using app-text/libetonyek
mspub Add support to mspub format using app-text/libmspub
mwaw Add support to mwaw formats using app-text/libmwaw
pagemaker Add support to pagemaker formats using media-libs/libpagemaker
visio Add support for visio format using media-libs/libvisio
wpd Add support for wpd format using app-text/libwpd
wpg Add support for wpg format using app-text/libwpg
wps Add support for wps format using app-text/libwps

wv

tools Install optional utilities considered deprecated in favor of using AbiWord.

xmlto

text Support conversion from XML to plain text

zathura

magic Use libmagic to determine mimetypes
synctex Use libsynctex to get latex codeline from pdf

zathura-meta

cb Install plug-in for ComicBook support

app-vim

gentoo-syntax

ignore-glep31 Remove GLEP 31 (UTF-8 file encodings) settings

youcompleteme

clang Enable semantic support for C-family languages using sys-devel/clang

dev-ada

asis

gnat_2016 Compile with dev-lang/gnat-gpl-2016
gnat_2017 Compile with dev-lang/gnat-gpl-2017
gnat_2018 Compile with dev-lang/gnat-gpl-2018

aunit

gnat_2016 Compile with dev-lang/gnat-gpl-2016
gnat_2017 Compile with dev-lang/gnat-gpl-2017
gnat_2018 Compile with dev-lang/gnat-gpl-2018

aws

gnat_2016 Compile with dev-lang/gnat-gpl-2016
gnat_2017 Compile with dev-lang/gnat-gpl-2017
gnat_2018 Compile with dev-lang/gnat-gpl-2018

gnat_util

gnat_2016 Compile with dev-lang/gnat-gpl-2016
gnat_2017 Compile with dev-lang/gnat-gpl-2017
gnat_2018 Compile with dev-lang/gnat-gpl-2018
shared Build gnat_util shared library
static-pic Build gnat_util static library with pic code

gnatcoll

gnat_2016 Compile with dev-lang/gnat-gpl-2016
gnat_2017 Compile with dev-lang/gnat-gpl-2017
projects Adds support for projects
pygobject Adds support for pygobject
shared Build shared library
tools Build associated tools

gnatcoll-bindings

gnat_2016 Compile with dev-lang/gnat-gpl-2016
gnat_2017 Compile with dev-lang/gnat-gpl-2017
gnat_2018 Compile with dev-lang/gnat-gpl-2018
shared Build shared library
static-pic Build shared library

gnatcoll-core

gnat_2016 Compile with dev-lang/gnat-gpl-2016
gnat_2017 Compile with dev-lang/gnat-gpl-2017
gnat_2018 Compile with dev-lang/gnat-gpl-2018
shared Build shared library
static-pic Build static library with pic code

gnatcoll-db

gnat_2016 Compile with dev-lang/gnat-gpl-2016
gnat_2017 Compile with dev-lang/gnat-gpl-2017
gnat_2018 Compile with dev-lang/gnat-gpl-2018
gnatcoll_db2ada Build gnatcoll_db2ada
gnatinspect Build gnatinspect
shared Build shared library
sql Build sql library
static-pic Build shared library
xref Build xref library

gnatmem

gnat_2016 Compile with dev-lang/gnat-gpl-2016
gnat_2017 Compile with dev-lang/gnat-gpl-2017
gnat_2018 Compile with dev-lang/gnat-gpl-2018

gprbuild

gnat_2016 Compile with dev-lang/gnat-gpl-2016
gnat_2017 Compile with dev-lang/gnat-gpl-2017
gnat_2018 Compile with dev-lang/gnat-gpl-2018

gtkada

gnat_2016 Compile with dev-lang/gnat-gpl-2016
gnat_2017 Compile with dev-lang/gnat-gpl-2017
gnat_2018 Compile with dev-lang/gnat-gpl-2018
shared Build gtkada as shared library

libadalang

gnat_2016 Compile with dev-lang/gnat-gpl-2016
gnat_2017 Compile with dev-lang/gnat-gpl-2017
gnat_2018 Compile with dev-lang/gnat-gpl-2018
shared Build shared library

libadalang-tools

gnat_2016 Compile with dev-lang/gnat-gpl-2016
gnat_2017 Compile with dev-lang/gnat-gpl-2017
gnat_2018 Compile with dev-lang/gnat-gpl-2018

libgpr

gnat_2016 Compile with dev-lang/gnat-gpl-2016
gnat_2017 Compile with dev-lang/gnat-gpl-2017
gnat_2018 Compile with dev-lang/gnat-gpl-2018
shared Build shared library
static-pic Build static library with pic code

xmlada

gnat_2016 Compile with dev-lang/gnat-gpl-2016
gnat_2017 Compile with dev-lang/gnat-gpl-2017
gnat_2018 Compile with dev-lang/gnat-gpl-2017
shared Build shared library
static-pic Build static library with pic code

dev-cpp

eigen

c++11 Build using the C++11 standard
cuda Build with cuda support

glog

gflags Use dev-cpp/gflags for flag parsing
unwind Use sys-libs/libunwind for stack unwinding instead of glibc/gcc (may be more reliable on x86_64)

libcmis

man Build and install man pages.

libjson-rpc-cpp

http-client Build support for HTTP client using net-misc/curl
http-server Build support for HTTP server using net-libs/libmicrohttpd
redis-client Build support for Redis client using dev-libs/hiredis
redis-server Build support for Redis server using dev-libs/hiredis
stubgen Build header stub code generator (needed for development and when pregenerated headers are not bundled)

sourcetrail

examples Install example projects.

websocketpp

boost Use dev-libs/boost instead of C++11

xsd

ace Enable support for serializing to/from an ACE CDR stream

dev-db

aerospike-server-community

tools Install extra tools

clickhouse

client Build CLI client.
kafka Enables support for kafka consumer.
mongodb Enabled support for MongoDB-based dictionaries
server Build server.
tools Build various tools, like benchmark, copier, etc.
zookeeper Enable support for clustering (based on Zookeeper).

cppdb

mysql_internal Don't build a separate mysql loadable module but rather build it into the cppdb library itself
odbc_internal Don't build a separate postgresql loadable module but rather build it into the cppdb library itself
postgres_internal Don't build a separate odbc loadable module but rather build it into the cppdb library itself
sqlite_internal Don't build a separate sqlite3 loadable module but rather build it into the cppdb library itself

etcd

server Installs etcd daemon

firebird

server Install the server components of Firebird, not just the client
xinetd Install ClassicServer

maatkit

udf Build the MySQL UDFs shipped with maatkit, requires non-minimal MySQL

mariadb

backup Build mariadb-backup which supports SST and hot backup of InnoDB, Aria and MyISAM including compression and encryption
client-libs Build the client libraries from the server package instead of the C Connector packages
extraengine Add support for alternative storage engines (Archive, CSV, Blackhole, Federated(X), Partition)
galera Enables galera replication
innodb-lz4 Enables lz4 compression methods for InnoDB/XtraDB
innodb-lzo Enables lzo compression methods for InnoDB/XtraDB
innodb-snappy Enables snappy compression methods for InnoDB/XtraDB using app-arch/snappy
jdbc Enable the CONNECT engine to access foreign databases via JDBC
latin1 Use LATIN1 encoding instead of UTF8
libressl Enable SSL connections and crypto functions using dev-libs/libressl
mroonga Add support for the Mroonga engine for interfacing with the Groonga text search
numa Enable NUMA support using sys-process/numactl (NUMA kernel support is also required)
oqgraph Add support for the Open Query GRAPH engine
pam Enable the optional PAM authentication plugin for the server
profiling Add support for statement profiling (requires USE=community).
rocksdb Add support for RocksDB; a key/value, LSM database optimized for flash storage
server Build the server program
sphinx Add suport for the sphinx full-text search engine
sst-mariabackup Add tools needed to support the mariabackup SST method
sst-rsync Add tools needed to support the rsync SST method
sst-xtrabackup Add tools needed to support the xtrabackup and xtrabackup-v2 SST methods
systemtap Build support for profiling and tracing using dev-util/systemtap
test Install upstream testsuites for end use.
tokudb Add support for TokuDB storage engine
yassl Enable SSL connections and crypto functions using the bundled yaSSL

mariadb-connector-c

mysqlcompat Enable mysqlclient library symbolic links

mariadb-galera

client-libs Build the client libraries from the server package instead of the C Connector packages
extraengine Add support for alternative storage engines (Archive, CSV, Blackhole, Federated(X), Partition)
jdbc Enable the CONNECT engine to access foreign databases via JDBC
latin1 Use LATIN1 encoding instead of UTF8
libressl Enable SSL connections and crypto functions using dev-libs/libressl
numa Enable NUMA support using sys-process/numactl (NUMA kernel support is also required)
oqgraph Add support for the Open Query GRAPH engine
profiling Add support for statement profiling (requires USE=community).
server Build the server program
sphinx Add suport for the sphinx full-text search engine
sst-rsync Add tools needed to support the rsync SST method
sst-xtrabackup Add tools needed to support the xtrabackup and xtrabackup-v2 SST methods
systemtap Build support for profiling and tracing using dev-util/systemtap
test Install upstream testsuites for end use.
tokudb Add support for TokuDB storage engine
yassl Enable SSL connections and crypto functions using the bundled yaSSL

mongodb

mms-agent Install the MongoDB Monitoring Service agent
tools Install the MongoDB tools (mongoimport, mongodump...) from app-admin/mongo-tools

mysql

cjk Add CJK support for InnoDB fulltext search using app-text/mecab
client-libs Build the client libraries from the server package instead of the C Connector packages (not recommended)
experimental Build experimental features aka "rapid" plugins
extraengine Add support for alternative storage engines (Archive, CSV, Blackhole, Federated(X), Partition)
latin1 Use LATIN1 encoding instead of UTF8
libressl Enable SSL connections and crypto functions using dev-libs/libressl
numa Enable NUMA support using sys-process/numactl (NUMA kernel support is also required)
profiling Add support for statement profiling (requires USE=community).
server Build the server program
systemtap Build support for profiling and tracing using dev-util/systemtap
test Install upstream testsuites for end use.
yassl Enable SSL connections and crypto functions using the bundled yaSSL

mysql-cluster

cluster Add support for NDB clustering
community Enables the community features from upstream.
embedded Build embedded server (libmysqld)
extraengine Add support for alternative storage engines (Archive, CSV, Blackhole, Federated(X), Partition)
latin1 Use LATIN1 encoding instead of UTF8
libressl Enable SSL connections and crypto functions using dev-libs/libressl
max-idx-128 Raise the max index per table limit from 64 to 128
minimal Install client programs only, no server
numa Enable NUMA support using sys-process/numactl (NUMA kernel support is also required)
openssl Enable SSL connections and crypto functions using dev-libs/openssl
profiling Add support for statement profiling (requires USE=community).
server Build the server program
systemtap Build support for profiling and tracing using dev-util/systemtap
test Install upstream testsuites for end use.
yassl Enable SSL connections and crypto functions using the bundled yaSSL

mysql-connector-c++

gcov Build coverage support
legacy Build the legacy 1.x API as well as the DevX API

oracle-instantclient

jdbc Support for XA, Internationalization, and RowSet operations under JDBC
odbc Libraries for enabling ODBC applications
precomp "proc" binary and related files to precompile a Pro*C application
sdk Header files and an example makefile for developing Oracle applications
sqlplus The SQL*Plus command line tool for SQL and PL/SQL queries
tools Data Pump, SQL*Loader and Workload Replay Client

percona-server

cjk Add CJK support for InnoDB fulltext search using app-text/mecab
client-libs Build the libmysqlclient libraries
experimental Build experimental features aka "rapid" plugins
latin1 Use LATIN1 encoding instead of UTF8
libressl Enable SSL connections and crypto functions using dev-libs/libressl
numa Enable NUMA support using sys-process/numactl (NUMA kernel support is also required)
profiling Add support for statement profiling (requires USE=community).
rocksdb Add support for RocksDB; a key/value, LSM database optimized for flash storage
server Build the server program
systemtap Build support for profiling and tracing using dev-util/systemtap
test-suite Install upstream testsuites for end use.
tokudb Add support for TokuDB storage engine
tokudb-backup-plugin Builds the TokuDB backup plugin
yassl Enable SSL connections and crypto functions using the bundled yaSSL

pgadmin3

databasedesigner Enable the Database Designer component

pgbouncer

c-ares Use c-ares as the DNS backend instead of evdns (libevent).
udns Use udns as the DNS backend instead of evdns (libevent). Supports IPv4 only.

pgpool2

memcached Use memcached for query caching.

pgrouting

drivingdistance Enable to calculate driving distance
html Install HTML formatted documentation

phpmyadmin

setup Installs the phpMyAdmin setup utility. Users who don't use the utility should disable this USE flag for security reasons as the setup tool was the target of various exploits in the past.

postgis

address-standardizer Normalize US and CA postal addresses
gtk Build graphical interface for shp2pgsql (shp2pgsql-gui)
mapbox Add capability to transform geometry into Mapbox Vector Tile
topology Build topology spatial types and functions

postgresql

llvm Add support for llvm JIT engine
pg_legacytimestamp Use double precision floating-point numbers instead of 64-bit integers for timestamp storage.
server Disable to build and install the clients and libraries only.
uuid Enable server side UUID generation (via dev-libs/ossp-uuid).

psqlodbc

iodbc Use dev-db/libiodbc. Disable to use dev-db/unixODBC.

redis

tcmalloc Use tcmalloc from dev-util/google-perftools for allocations.

rethinkdb

tcmalloc Use tcmalloc from dev-util/google-perftools for allocations.

soci

boost Enable boost support
empty Build the sample backend called Empty

spatialite

geos Add the sci-libs/geos library for exact topological tests
proj Add the sci-libs/proj library for reprojection features
xls Add the dev-libs/freexl library for xls import support

sqldeveloper

sybase Add support for the Sybase SQL Database Server

sqlite

secure-delete Enable overwriting of deleted content with zeros by default (http://sqlite.org/pragma.html#pragma_secure_delete), causing some performance penalty
tools Install additional tools

sqlitestudio

cli Build CLI interface

tokumx

pax_kernel Apply patch needed for hardened kernels

unixODBC

minimal Disable bundled drivers and extra libraries (most users don't need these)
odbcmanual Administrator, Internal Structure, Programmer and User documentation

dev-embedded

avrdude

ftdi Enable support for USB FTDI chips via dev-embedded/libftdi

libftdi

tools build ftdi_eeprom helper tool

openocd

cmsis-dap Support for CMSIS-DAP compliant adapters
dummy Build the dummy port driver
ftdi Enable support for USB FTDI chips via dev-embedded/libftdi
jlink Build the SEGGER J-Link driver
parport Enable support for parport JTAG devices
verbose-io Verbose IO and comm JTAG and USB messages

sdcc

avr Add support for AVR -- not supported upstream
boehm-gc Enable Hans Boehm's garbage collector dev-libs/boehm-gc
device-lib Enable built of devices libraries
ds390 Add support for Dallas DS390
ds400 Add support for Dallas DS400
gbz80 Add support for Gameboy gbz80
hc08 Add support for Freescale/Motorola HC08 based
mcs51 Add support for Intel mcs51
non-free Enable non-free runtime library parts
packihx Enable Intel HEX files pack utility
pic14 Add support for Microchip 14 bits PICs
pic16 Add support for Microchip 16 bits PICs
r2k Add support for Rabbit 2000
r3ka Add support for Rabbit 3000A
s08 Add support for Freescale/Motorola S08
sdbinutils Enable SDCC library archive utilities sdar, sdranlib, sdnm
sdcdb Enable SDCC source level debugger
sdcpp Enable SDCC preprocessor based on GCC cpp
stm8 Add support for STMicroelectronics STM8
tlcs90 Add support for TLCS-90
ucsim Enable software simulator for microcontrollers
z180 Add support for Zilog Z180
z80 Add support for Zilog Z80

urjtag

ftd2xx Enable support for USB FTDI chips via dev-embedded/libftd2xx
ftdi Enable support for USB FTDI chips via dev-embedded/libftdi

dev-games

aseprite

bundled-libs Use the upstream provided bundled version of allegro 4.4.2
gtk3 Enable support for the experimental native GTK File Dialog

cegui

devil Build the DevIL based ImageCodec module
freeimage Build the FreeImage based ImageCodec module
irrlicht Enable the Irrlicht renderer
ogre Enable the OGRE renderer
tinyxml Enable the Tiny XML parser module
xerces-c Enable the Xerces-C++ XML parser module
zip Enable the Minizip resource provider

guichan

allegro Build the Allegro frontend

mygui

l10n_ru Install some additional russian docs if 'doc' useflag enabled
ogre Use the ogre render subsystem. (cannot combine with opengl)
opengl Use the opengl render subsystem. (cannot combine with ogre)
plugins Build MyGUI plugins
samples Install MyGUI demos (needs ogre USE flag)
tools Build the tools for development

ode

double-precision more precise calculations at the expense of speed
gyroscopic enable gyroscopic term (may cause instability)

ogre

boost Enable boost support
cache Enable GL state cache support
cg NVIDIA toolkit plugin
double-precision More precise calculations at the expense of speed
egl Use egl instead of glx
experimental Build experimental BETA component 'HLMS'
freeimage Support images via media-libs/freeimage
gl3plus Build OpenGL 3+ RenderSystem (EXPERIMENTAL)
gles2 Build OpenGL ES 2.x RenderSystem
gles3 Enable OpenGL ES 3.x Features
json Use dev-libs/rapidjson (needed by Hlms JSON materials)
legacy-animations Use the skeletal animation from 1.x. It's much slower, but the new system is still experimental.
mobile Build for OpenGL ES 2.0 only and use the mobile variants of the PBS and unlit material systems.
ois Pull in Object-oriented Input System library dev-games/ois for samples
poco When USE=threads, use poco for threading
resman-pedantic Resource Manager PEDANTIC : require an explicit resource group. Case sensitive lookup. Some demos might not work with this setting. (default: case-insensitive + sensitive lookup in all groups)
resman-strict Resource Manager STRICT : search in default group if not specified otherwise. Case sensitive lookup. Some demos might not work with this setting. (default: case-insensitive + sensitive lookup in all groups)
tbb When USE=threads, use tbb for threading
tools Build and install helper tools

openscenegraph

asio Enable support for dev-cpp/asio library
fox Build examples using x11-libs/fox library
gdal Enable support for sci-libs/gdal library
las Enable support for geospatial data LAS LiDAR format using sci-geosciences/liblas
openinventor Build OpenInventor plugin
osgapps Build osg applications
sdl2 Use media-libs/libsdl2 additionally to media-libs/libsdl
xrandr Enable support for the X xrandr extension

physfs

7zip Enable 7zip/lzma archive support
grp Enable Build Engine GRP archive support
hog Enable Descent I/II HOG archive support
iso Enable ISO9660 file support
mvl Enable Descent I/II MVL archive support
qpak Enable Quake I/II QPAK archive support
slb Enable Independence War SLB archive support
vdf Enable Gothic/Gothic II VDF archive support
wad Enable Doom WAD archive support

simgear

dns Enable DNS resolver via net-libs/udns
gdal Enable alternative terrain engine based on pagedLOD via sci-libs/gdal
subversion Enable terrasync scenery downloader

dev-haskell

abstract-deque

usecas Enable the reference implementation to use hardware compare-and-swap.

aeson-pretty

lib-only don't build 'aeson-pretty' executable.

ansi-terminal

example Build the example application.

ansi-wl-pprint

example Build the example application.

authenticate

network-uri Get Network.URI from the network-uri package

bifunctors

semigroups You can disable the use of the `semigroups` package using `-f-semigroups`. Disabing this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.
tagged You can disable the use of the `tagged` package using `-f-tagged`. Disabing this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.

biosff

fclip Build the fclip executable.
flower Build the flower executable.
frecover Build the frecover executable.

blaze-builder-enumerator

newbuilder use bytestring-builder instead of blaze-builder-0.3

bytedump

executable build executable file

bytes

test-doctests Enable the doctest suite when using the enable-tests option for cabal.

c2hs

regression run regression tests

cabal-install

network-uri Get Network.URI from the network-uri package.
noprefs Ignore 'preferred-versions' file from hackage's tarball.

certificate

executable Build the executable

cgi

extensible-exceptions-in-base Required to be enabled for >=dev-lang/ghc-7.
network-uri Get Network.URI from the network-uri package.

chell

color-output use colors in program output

citeproc-hs

bibutils use Chris Putnam's app-text/bibutils
embed_data_files Embed locale files into the library (needed for windows packaging)
hexpat use dev-haskell/hexpat instead of dev-haskell/xml for XML parsing
network use dev-haskell/network and dev-haskell/http to retrieve CSL file from URIs
small_base Choose the new smaller, split-up base package.
unicode_collation Use Haskell bindings to the dev-libs/icu

cmark

system-cmark use app-text/cmark instead of bundled copy

cmdargs

quotation Build quote module
testprog Build the test program

comonad

containers You can disable the use of the `containers` package using `-f-containers`. Disabing this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.
contravariant You can disable the use of the `contravariant` package using `-f-contravariant`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. If disabled we will not supply instances of `Contravariant`
distributive You can disable the use of the `distributive` package using `-f-distributive`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. If disabled we will not supply instances of `Distributive`
test-doctests Run the doctests test suite

conduit

nohandles experimental code to use raw system calls in place of handles. Not recommended for general use

configfile

buildtests Build the executable to run unit tests.

contravariant

safe Get Safe guarantees rather than merely Trustworthy, but with worse constant factors.
semigroups You can disable the use of the `semigroups` package using `-f-semigroups`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.
statevar You can disable the use of the `StateVar` package using `-f-StateVar`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.
tagged You can disable the use of the `tagged` package on older versons of GHC using `-f-tagged`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.

cpu

executable build 'cpuid' tool

crypto-api

all_cpolys Build all the CMAC polynomes up to 10000 bits instead of just the usual ones

crypto-conduit

conduit11 Use conduit >= 1.1.

cryptohash

cryptoapi Defines crypto-api instances

cryptonite

integer-gmp Whether or not to use GMP for some functions
support_aesni allow compilation with AESNI on system and architecture that supports it
support_blake2_sse Use SSE optimized version of BLAKE2
support_deepseq add deepseq instances for cryptographic types
support_pclmuldq Allow compilation with pclmuldq on architecture that supports it
support_rdrand allow compilation with AESNI on system and architecture that supports it

dav

network-uri Get Network.URI from the network-uri package.

distributive

lib-werror Compile with the ghc -Werror option

encoding

systemencoding Provide the getSystemEncoding action to query the locale.

entropy

halvm Build for the HaLVM.

filestore

maxcount Make use of a recent (>= 2.3.0) Darcs feature which vastly improves the performance of 'latest'. You should disable this flag if you plan to use gitit with an older version of Darcs, or 'latest' will raise an error.

glib

closure_signals Use the the GClosure-based signals implementation.

gtk

deprecated Include definitions in this library that are considered obsolete.
fmode-binary Set the default file translation mode for file I/O operations to _O_BINARY.
gio Depend on GIO package, thereby enabling certain features.

gtk2hs-buildtools

closuresignals Use the the GClosure-based signals implementation.

gtk3

fmode-binary Set the default file translation mode for file I/O operations to _O_BINARY.
gio Depend on GIO package, thereby enabling certain features.

hackage-security

use-network-uri Get Network.URI from the network-uri package.

happstack-server

network-uri Get Network.URI from the network-uri package
template_haskell Description: Template Haskell is available on this system

hashed-storage

diff Provide the Storage.Hashed.Diff module.
hpc Compile with the profiling ghc flag -fhpc.

hashtables

bounds-checking if on, use bounds-checking array accesses
portable if on, use only pure Haskell code and no GHC extensions.
unsafe-tricks turn on unsafe GHC tricks

haskeline

legacy-encoding Use legacy iconv encoding for POSIX. This is only intended for testing.
libiconv Explicitly link against the libiconv library.
terminfo Use the terminfo package for POSIX consoles.

hdbc-odbc

buildstresstest Build stress test

hdbc-sqlite3

buildtests Build the executable to run unit tests
splitbase Choose the new smaller, split-up package.

hexpat

bundled-expat Use bundled expat instead of dev-libs/expat

highlighting-kate

executable Build the Highlight executable.
pcre-light Use the pcre-light library instead of regex-pcre-builtin.

hit

executable Build the executable

hlint

gpl Use GPL libraries, specifically hscolour.

hps

build-exec Build the `hps-fractals' executable

hs3

network-uri Get Network.URI from the network-uri package.

hslogger

buildtests Build the executable to run unit tests.

hslua

apicheck Compile Lua with -DLUA_USE_APICHECK..
system-lua Use the system-wide lua instead of the bundled copy.

hsopenssl

fast-bignum Enable fast moving of bignums between OpenSSL and GMP (GHC Only)

http

conduit10 Use version 1.0.x or below of the conduit package (for the test suite).
network-uri Get Network.URI from the network-uri package.

http-api-data

use-text-show Use text-show library for efficient ToHttpApiData implementations

http-client

network-uri Get Network.URI from the network-uri package.

http-streams

network-uri Get Network.URI from the network-uri package.

httpd-shed

buildexamples Build example executables.
network-uri Get Network.URI from the network-uri package.

hxt

network-uri Get Network.URI from the network-uri package.

icalendar

network-uri use network-uri package

json

generic Add support for generic encoder (dev-haskell/syb)
mapdict Encode Haskell maps as JSON dicts
parsec Add support for parsing with Parsec
pretty Add support for using pretty printing combinators

language-dot

executable Build the `ppdot' executable

lens

benchmark-uniplate Enable benchmarking against Neil Mitchell's uniplate library for comparative performance analysis. Defaults to being turned off to avoid the extra dependency.
dump-splices Build and run the doctests test-suite.
inlining Generate inline pragmas when using template-haskell. This defaults to enabled, but you can to shut it off to benchmark the relative performance impact, or as last ditch effort to address compile errors resulting from the myriad versions of template-haskell that all purport to be 2.8.
j Attempt a parallel build with GHC 7.8.
lib-werror Turn on ghc-options: -Werror
old-inline-pragmas Some 7.6.1-rc1 users report their TH still uses old style inline pragmas. This lets them turn on inlining.
safe Disallow unsafeCoerce
test-doctests Build and run the doctests test-suite.
test-hlint You can disable the hlint test suite with -f-test-hlint
test-hunit You can disable the hunit test suite with -f-test-hunit
test-properties Build the properties test if we're building tests
test-templates Build the test templates if we're building tests
trustworthy Assert that we are trustworthy when we can

lifted-async

monad-control-1 Use moand-control == 1.*

linear

template-haskell You can disable the use of the `template-haskell` package using `-f-template-haskell`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.

monad-control

instancest If enabled this package will export MonadBaseControl instances for the lazy and strict ST monad. If disabled these instances are only exported when base >= 4.4. If enabled it is required that the transformer-base package exports MonadBase instances for ST. It will do this by default.

monad-logger

template_haskell Enable Template Haskell support.

monad-par

chaselev Use Chase-Lev Deques for higher-perf work-stealing.

nats

hashable You can disable the use of the `hashable` package using USE=-hashable. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. If set we will not supply an instance of `Hashable`.

network-data

small_base Build the split-up base package.

pandoc-citeproc

bibutils use Chris Putnam's app-text/bibutils
embed_data_files Embed locale files into the library (needed for windows packaging)
hexpat use dev-haskell/hexpat instead of dev-haskell/xml for XML parsing
network use dev-haskell/network and dev-haskell/http to retrieve CSL file from URIs
small_base Choose the new smaller, split-up base package.
test_citeproc Build the test-citeproc program
unicode_collation Use Haskell bindings to the dev-libs/icu

persistent

nooverlap Use OverlappingInstances only for String. Only developers should use this.

persistent-sqlite

build-sanity-exe Build a sanity check test executable.

pointed

comonad optional instances
containers optional instances
kan-extensions optional instances
semigroupoids optional instances
semigroups optional instances
stm optional instances
tagged optional instances
transformers optional instances
unordered-containers optional instances

publicsuffixlist

create export Network.PublicSuffixList.Create module
runtimelist read suffix list from dist at startup instead of embedding list into library

quickcheck

template_haskell Enable additional test modules requiring Template Haskell support.

recaptcha

network-uri Get Network.URI from the network-uri package.

reflection

template-haskell Enable template haskell.

rfc5051

mkunicodedata build codes generator itself

sandi

with-conduit Build with conduit

scientific

bytestring-builder Provide the Data.ByteString.Builder.Scientific module (requires bytestring >= 0.10).

semigroupoid-extras

profunctors You can disable the use of the `profunctors` package using `-f-profunctors`. Disabing this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.

semigroupoids

comonad You can disable the use of the `comonad` package using `-f-comonad`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. If disabled we will not supply instances of `Comonad`
containers You can disable the use of the `containers` package using `-f-containers`. Disabing this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.
contravariant You can disable the use of the `contravariant` package using `-f-contravariant`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. If disabled we will not supply instances of `Contravariant`
distributive You can disable the use of the `distributive` package using `-f-distributive`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. If disabled we will not supply instances of `Distributive`
tagged You can disable the use of the `tagged` package using `-f-tagged`. Disabing this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.

semigroups

binary provide instances for binary package
bytestring You can disable the use of the `bytestring` package using USE=-bytestring. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.
containers You can disable the use of the `containers` package using USE=-containers. Disabing this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.
deepseq You can disable the use of the `deepseq` package using `-f-deepseq`. Disabing this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.
hashable You can disable the use of the `hashable` package using USE=-hashable. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. If set we will not supply an instance of `Hashable`.
text You can disable the use of the `text` package using USE=-text. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.
transformers provide instances for transformers package.
unordered-containers You can disable the use of the `unordered-containers` package using USE=-unordered-containers. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.

sendfile

portable Explicitly enable portable sendfile support (implemented in Haskell)

sha

exe Build a sha1 and a sha384 executable similar to 'md5sum'.

shakespeare

test_coffee Render tests through coffeescript render function.
test_export Test export.
test_roy Render tests through roy render function.

shakespeare-js

test_coffee Test coffee.
test_export Test export.
test_roy Test roy.

shelly

lifted run the tests against Shelly.Lifted

shuffle

network-uri Get Network.URI from the network-uri package.

simple-sendfile

allow-bsd Allow use of BSD sendfile (disable on GNU/kFreeBSD)

skein

big-endian When manually selecting the endianness, use big-endian (default is little-endian)
force-endianness Use a manually selected endian when compiling (see flag 'big-endian')
reference Use the reference implementation instead of the optimized one

skylighting

executable Build the skylighting executable.

snap-core

portable No non-haskell unportable code.

snap-server

build-pong Build a server that just returns "PONG"
openssl enable https support using dev-haskell/hsopenssl
portable no non-haskell unportable code.

tagsoup

download Build with Download module.
testprog Build the test program.

tasty

colors Enable colorful output

tasty-quickcheck

old-quickcheck Use Quick-Check < 2.7.

texmath

executable Compile test executable.
network-uri Get Network.URI from the network-uri package.

text

developer operate in developer mode

thyme

bug-for-bug bug-for-bug compatibility with time
lens use the full lens package
show-internal instance Show of internal representation

tls

compat Accept SSLv2 compatible handshake.
network Use the base network library.

transformers-base

orphaninstances Build instances for orphan datatypes.

transformers-compat

three Use transformers-0.3

unix-compat

old-time build against old-time package

uuagc

with-loag Use dev-haskell/minisat external SAT-solver to schedule all Linear Ordered AGs.

vector

boundschecks Enable bounds checking
internalchecks Enable internal consistency checks at the cost of a significant performance penalty
unsafechecks Enable bounds checking in unsafe operations at the cost of a significant performance penalty

vector-algorithms

bench Build a benchmarking program.
boundschecks Enable bounds checking.
internalchecks Enable internal consistency checks at the cost of a significant performance penalty.
properties Enable quickcheck tests.
unsafechecks Enable bounds checking in unsafe operations at the cost of a significant performance penalty.

void

safe dissable effective but unsafe coersions

wai-app-static

print print debug info.

warp

allow-sendfilefd Allow use of sendfileFd (not available on GNU/kFreeBSD).
warp-debug Add additional debuging information

x11

screensaver whether to build XScreenSaver.

x509-store

executable Build the executable

xss-sanitize

network-uri Get Network.URI from the network-uri package.

yaml

no-examples don't build the examples
no-exe don't install the yaml2json executable
no-unicode Don't enable unicode output. Instead, unicode characters will be escaped.
system-libyaml Use system libyaml instead on generic one

yesod-auth

network-uri Get Network.URI from the network-uri package

yesod-form

network-uri Get Network.URI from the network-uri package

zip-archive

executable Build the Zip executable.

zlib

non-blocking-ffi Execute FFI calls in the context of haskell thread.

dev-java

ant

antlr Enable ANTLR Ant tasks
bcel Enable bcel (bytecode manipulation) Ant tasks
bsf Enable support for Apache Bean Scripting Framework (dev-java/bsf)
commonslogging Enable commons-logging Ant tasks
commonsnet Enable commons-net Ant tasks
jai Enable JAI (Java Imaging) Ant task
javamail Enable JavaMail Ant task
jdepend Enable Jdepend Ant tasks
jmf Enable JMF (Java Media Framework) Ant tasks
jsch Disable Jsch (ssh, scp and related) Ant tasks
log4j Enable Apache log4j Ant tasks
oro Enable Apache Oro Ant tasks
regexp Enable Apache Regexp Ant tasks
resolver Enable Apache Resolver Ant tasks
testutil Enable optional test util classes

commons-collections

test-framework Install the test framework

commons-logging

avalon-framework Add optional support for avalon-framework
avalon-logkit Add optional support for avalon-logkit
log4j Add optional support for log4j
servletapi Add optional support for servletapi

ecj-gcj

native Build a native binary along with the jar. Provides faster execution time, but needs about 1G memory and some patience to compile.

eclipse-ecj

ant Support using ecj in Ant builds via dev-java/ant-eclipse-ecj

emma

launcher Install /usr/bin/emma. Collides with sci-biology/emboss.

gcj-jdk

awt Install AWT libraries, needed by some GUIs (not needed to build icedtea)

gnu-classpath

alsa Build with ALSA javax.sound.midi provider
dssi Build with DSSI javax.sound.midi provider
gconf Build with GConf preferences backend
gjdoc Build GJDoc, a documentation generator
gmp Build with GMP backend for java.math.BigInteger
gtk Build with Gtk+ AWT peers
xml Build with native XML backend

icedtea

cacao Use the CACAO virtual machine rather than HotSpot.
cups Link against the CUPS library at compile time, rather than using it dynamically at runtime.
headless-awt Don't install the X backend for AWT, needed by some GUIs (used to be X flag)
jamvm Use the JamVM virtual machine rather than HotSpot.
jbootstrap If possible, recompile the final IcedTea executables with itself.
kerberos Link against Kerberos in order to obtain the cache location.
nsplugin Enable browser plugin (NPPlugin), requires also the webstart flag to be enabled.
pax_kernel Apply patch needed for pax enabled kernels.
pch Build using pre-compiled headers.
sctp Build the SCTP NIO channel implementation against lksctp
shenandoah Include the Shenandoah ultra-low pause time garbage collector (-XX:+UseShenandoahGC) (arm64 and x86_64 only)
smartcard Build the PCSC driver against pcsc-lite
sunec Build the SunEC provider against system NSS
system-lcms Build against the system LCMS installation rather than the in-tree copy.
webstart Enable Web Start support (via NetX).
zero Enable Zero assembler port (usually for non-HotSpot architectures)

icedtea-bin

headless-awt Don't install the X backend for AWT, needed by some GUIs (used to be X flag)
webstart Provide javaws command through symlink to icedtea-web

icedtea-web

javascript Enable support for using proxy auto config (PAC) files.
nsplugin Enable the browser plugin (NPPlugin).
tagsoup Depend on dev-java/tagsoup which allows parsing malformed .jnlp files

itext

rtf Build and provide libraries for rich text format
rups Build and provide GUI for Reading/Updating PDF Syntax

jcs

admin Enable JCS Admin servlets

jdbc-mysql

c3p0 Enable c3p0 support
log4j Enable log4 support

jfreesvg

debug Enable debugging during compilation.

jna

awt Enables support for Java AWT
nio-buffers Enables support for NIO buffers

log4j

javamail Build the SMTPAppender
jms Build the JMSAppender

logback

tomcat Builds Apache Tomcat support

lucene

contrib Include extra functionality from contrib/

miglayout

swt Add support for the SWT toolkit.

openjdk

gentoo-vm Allow this JDK to be recognised by Gentoo (package manager, eselect, java-config, EXPERIMENTAL!)
headless-awt Don't install the X backend for AWT, needed by some GUIs
jbootstrap Build OpenJDK twice, the second time using the result of the first
source Install JVM sources
webstart Provide javaws command through symlink to icedtea-web

openjdk-bin

gentoo-vm Allow this JDK to be recognised by Gentoo (package manager, eselect, java-config, EXPERIMENTAL!)
headless-awt Don't install the X backend for AWT, needed by some GUIs (used to be X flag)
source Install JVM sources
webstart Provide javaws command through symlink to icedtea-web

oracle-jdk-bin

commercial Install features requiring a commercial license for production use
gentoo-vm Allow this JDK to be recognised by Gentoo (package manager, eselect, java-config, EXPERIMENTAL!)
gtk2 Enable GTK+ 2 support in JavaFX
gtk3 Enable GTK+ 3 support in JavaFX
headless-awt Don't install the X backend for AWT, needed by some GUIs (used to be X flag)
javafx Install JavaFX libraries
jce Install Java Cryptographic Extension Unlimited Strength Jurisdiction Policy Files
source Install JVM (and optionally JavaFX) sources
visualvm Install VisualVM debugging tool

oracle-jre-bin

commercial Install features requiring a commercial license for production use
gentoo-vm Allow this JRE to be recognised by Gentoo (package manager, eselect, java-config, EXPERIMENTAL!)
gtk2 Enable GTK+ 2 support in JavaFX
gtk3 Enable GTK+ 3 support in JavaFX
headless-awt Don't install the X backend for AWT, needed by some GUIs (used to be X flag)
javafx Install JavaFX libraries
jce Install Java Cryptographic Extension Unlimited Strength Jurisdiction Policy Files

proguard

ant Ant task for using ProGuard in build.xml scripts

protobuf-java

nano Enable code generator and runtime library designed specifically for resource-constrained systems, like Android

rxtx

lfd Installs and uses LockFileServer daemon (lfd)

sbt

binary Install from (Gentoo-compiled) binary instead of building from sources. Set this when you run out of memory during build.

dev-lang

bas

lr0 Use the LR0 parser instead of the recursive descending parser

crystal

blocking-stdio-hack Keep STDIO file descriptors in blocking mode.
debug Build each module as a separate object file. Speeds build up.
xml Use the dev-libs/libxml2 library to enable Crystal xml module
yaml Use the dev-libs/libyaml library to enable Crystal yaml module

erlang

compat-ethread Enable compatibility with pre-pentium 4 CPUs in the ethread library.
dirty-schedulers Enable dirty schedulers
hipe HIgh Performance Erlang extension
kpoll Enable kernel polling support
pgo Build erts with profile-guided optimizations

fpc

ide Build and install the Free Pascal Compiler IDE

gdl

eigen Build matrix manipulation with dev-cpp/eigen
grib Add support for the meteorological GRIB format with sci-libs/grib_api
gshhs Add support for projection adn continent maps with sci-geosciences/gshhs-data
hdf Add support for the Hierarchical Data Format v.4
proj Add support for sci-libs/proj (geographic projections)
udunits Add support for manipulating units of physical quantities

ghc

binary Install the binary version directly, rather than using it to build the source version.
ghcbootstrap Internal: Bootstrap GHC from an existing GHC installation.
ghcmakebinary Internal: Build binary friendly for redistribution.

gnat-gpl

awt Useful only when building GCJ, this enables Abstract Window Toolkit (AWT) peer support on top of GTK+
cilk Support the Cilk Plus language (C/C++ based languages for parallel programming)
fixed-point Enable fixed-point arithmetic support for MIPS targets in gcc (Warning: significantly increases compile time!)
go Build the GCC Go language frontend.
graphite Add support for the framework for loop optimizations based on a polyhedral intermediate representation
libssp Build SSP support into a dedicated library rather than use the code in the C library (DO NOT ENABLE THIS IF YOU DON'T KNOW WHAT IT DOES)
mpx Enable support for Intel Memory Protection Extensions (MPX)
nopie Disable PIE support (NOT FOR GENERAL USE)
nossp Disable SSP support (NOT FOR GENERAL USE)
objc Build support for the Objective C code language
objc++ Build support for the Objective C++ language
objc-gc Build support for the Objective C code language Garbage Collector
pgo Build GCC using Profile Guided Optimization (PGO)
regression-test Run the testsuite and install the results (requires FEATURES=test)
sanitize Build support for various sanitizer functions (ASAN/TSAN/etc...)
ssp Build packages with stack smashing protector on by default
vtv Build support for virtual table verification (a C++ hardening feature)

go

gccgo Enable bootstrapping using gccgo

icon

iplsrc install the icon programming library source

lazarus

minimal Don't build extra packages from the bigide component

logtalk

fop Support for generating pdf documentation using fop
xslt Support for generating html documentation using xslt

lua

deprecated make deprecated data structures/routines available

luajit

lua52compat Enable some upwards-compatible features from Lua 5.2 that are unlikely to break existing code.

mercury

erlang Support Mercury Erlang grade
trail Support Mercury trail grades

mlton

binary install a binary version
bootstrap-smlnj Boostrap mlton with dev-lang/smlnj (takes a long time)
pax_kernel Enable if the user plans to run the package under a pax enabled hardened kernel
stage3 After bootstrap building mlton with dev-lang/smlnj, rebuild mlton with the second stage build of mlton (recommended).

moarvm

asan Enable clang's Address Sanitizer functionality. Expect longer compile time.
clang Use clang compiler instead of GCC
jit Enable Just-In-Time-Compiler. Has no effect except on AMD64 and Darwin.
optimize Enable optimization via CFLAGS
ubsan Enable clang's Undefined Behavior Sanitizer functionality. Expect longer compile time.

mono

pax_kernel Enable if the user plans to run the package under a pax enabled hardened kernel
xen Make mono generate code that is considerably faster on xen VMs but slightly slower on for normal systems.

nqp

clang Toggle usage of the clang compiler in conjunction with MoarVM
moar Build the MoarVM backend (experimental/broken)

ocaml

flambda Enables the Flambda optimizer: A new intermediate representation (introduced in ocaml 4.03) in the depths of the compiler designed to allow for better inlining.
spacetime Enables the Spacetime memory profiler. See https://caml.inria.fr/pub/docs/manual-ocaml/spacetime.html for more information.

orc

pax_kernel Apply patch needed for pax enabled kernels.

perl

ithreads Enable Perl threads, has some compatibility problems

php

argon2 Enable password hashing algorithm from app-crypt/argon2
bcmath Add support for libbcmath
cli Enable CLI SAPI
coverage Include gcov symbols for test coverage and lcov reports. Only useful for extension developers, and requires GCC.
ctype Enable ctype functions
embed Enable embed SAPI
enchant Add supports Enchant spelling library.
fileinfo Add fileinfo extension support
filter Add filter extension support
flatfile Add dbm support for flat files
fpm Enable the FastCGI Process Manager SAPI
gd Adds support for gd (bundled with PHP)
hash Enable the hash extension
inifile Add dbm support for .ini files
intl Enables the intl extension for extended internalization support
json Enable JSON support
ldap-sasl Add SASL support for the PHP LDAP extension
libmysqlclient Use libmyslclient driver for mysql, mysqli, PDO_Mysql (not recommended)
lmdb Enable support for dev-db/lmdb db backend
opcache Enables built-in opcode cache, replacing pecl-apc et al.
pcntl Add support for process creation functions
pdo Enable the bundled PDO extensions
phar Enables the phar extension to provide phar archive support
phpdbg Enable the PHP Debug Command Line SAPI (like gdb for php)
session-mm Include dev-libs/mm support for session storage
sharedmem Add support for shared memory use
simplexml Support for SimpleXML
sodium Enable support for crypto through dev-libs/libsodium
sybase-ct Add support for Sybase-CT
sysvipc Support for System V-compatible inter-process communication
tokenizer Add support for the PHP file parser
tokyocabinet Enable support for dev-db/tokyocabinet db backend
vpx Enable webp support for GD in php-5.x
wddx Add support for Web Distributed Data eXchange
webp Enable webp support for GD in php-7.x
xmlreader Enable XMLReader support
xmlwriter Enable XMLWriter support
xslt Enable the XSL extension
zip-encryption Enable ZIP file encryption from dev-libs/libzip

polyml

portable Build the portable interpreter version of Poly/ML instead of native

python

bluetooth Build Bluetooth protocol support in socket module
threads Enable threading support. (DON'T DISABLE THIS UNLESS YOU KNOW WHAT YOU'RE DOING)
wide-unicode Enable wide Unicode implementation which uses 4-byte Unicode characters. Switching of this USE flag changes ABI of Python and requires reinstallation of many Python modules. (DON'T DISABLE THIS UNLESS YOU KNOW WHAT YOU'RE DOING)
wininst Install Windows executables required to create an executable installer for MS Windows.

qu-prolog

pedro Pedro subscription/notification communications system

rakudo

clang Use Clang to compile the MoarVM backend
moar Use the MoarVM as backend

ruby

rdoc Install dev-ruby/rdoc after installing Ruby.
readline Use the sys-libs/readline library to provide the readline extension, used for instance by the irb tool. This flag is meaningful only if the libedit USE flag is disabled. If neither libedit nor readline USE flags are enabled, the readline extension will not be built (and irb will lose line editing functionality).
rubytests Install ruby tests that can only be run after ruby is installed

rust

cargo Install cargo component
clippy Install clippy component
rls Install rls component
rustfmt Install rustfmt component
system-llvm Use the system LLVM install
wasm Build support for the wasm32-unknown-unknown target

rust-bin

cargo Install cargo component
clippy Install clippy component
rustfmt Install rustfmt component

scala

binary Install from (Gentoo-compiled) binary instead of building from sources. Set this when you run out of memory during build.

smlnj

pax_kernel Enable if the user plans to run the package under a pax enabled hardened kernel

spidermonkey

custom-optimization Build with user-specified compiler optimizations (-Os, -O0, -O1, -O2, -O3) from CFLAGS (unsupported)
debug Enable assertions to allow for easier debugging of programs that link to spidermonkey -- note this will often crash software on regular end-user systems
system-icu Use the system-wide dev-libs/icu instead of bundled -- note, only takes effect when icu flag is enabled
threadsafe Build a threadsafe version of spidermonkey

swi-prolog

archive Use libarchive for extension packs
uuid Use ossp-uuid for UUID pack
yaml Use libyaml for YAML pack

swig

ccache build ccache-swig(a fast compiler cache)

yap

R Enable support for connecting R to Prolog

dev-libs

ace

ciao Include Component Intergraced Ace ORB into the build of ace
tao Include the ACE ORB (CORBA stuff) (called tao) into the build of ace

actor-framework

benchmarks Due to the number of out-of-tree deps, these only get installed as docs
boost Make use of Boost's ASIO functionality
cash Build the C Actor Shell for introspection and debugging
debug Raises log-level to DEBUG, enables runtime checks and address sanitizer
doc Compiles and installs the documentation as PDF and HTML
examples Installs the provided example source files
mem_management Enables built-in memory management
nexus Nexus is the central component for CAF's runtime inspection
opencl Compiles against the provided opencl implementation
riac Runtime inspection and configuration
static Provides a static build
test Builds the provided unit tests

antlr-c

debugger Compiles debug info into the library

appstream

apt Enables Debians APT support

appstream-glib

stemmer Add word stemming via dev-libs/snowball-stemmer.

apr

older-kernels-compatibility Enable binary compatibility with older kernels
urandom Use /dev/urandom instead of /dev/random

apr-util

libressl Use dev-libs/libressl instead of dev-libs/openssl for 'openssl' USE flag
nss Install apr_crypto_nss module
openssl Install apr_crypto_openssl module

atcore

gui Build test GUI

aws-sdk-cpp

aws_targets_AWSMigrationHub SDK Support for AWS AWSMigrationHub
aws_targets_access-management SDK Support for AWS access-management
aws_targets_acm SDK Support for AWS acm
aws_targets_acm-pca SDK Support for AWS acm-pca
aws_targets_alexaforbusiness SDK Support for AWS alexaforbusiness
aws_targets_apigateway SDK Support for AWS apigateway
aws_targets_application-autoscaling SDK Support for AWS application-autoscaling
aws_targets_appstream SDK Support for AWS appstream
aws_targets_appsync SDK Support for AWS appsync
aws_targets_athena SDK Support for AWS athena
aws_targets_autoscaling SDK Support for AWS autoscaling
aws_targets_autoscaling-plans SDK Support for AWS autoscaling-plans
aws_targets_batch SDK Support for AWS batch
aws_targets_budgets SDK Support for AWS budgets
aws_targets_ce SDK Support for AWS ce
aws_targets_cloud9 SDK Support for AWS cloud9
aws_targets_clouddirectory SDK Support for AWS clouddirectory
aws_targets_cloudformation SDK Support for AWS cloudformation
aws_targets_cloudfront SDK Support for AWS cloudfront
aws_targets_cloudhsm SDK Support for AWS cloudhsm
aws_targets_cloudhsmv2 SDK Support for AWS cloudhsmv2
aws_targets_cloudsearch SDK Support for AWS cloudsearch
aws_targets_cloudsearchdomain SDK Support for AWS cloudsearchdomain
aws_targets_cloudtrail SDK Support for AWS cloudtrail
aws_targets_codebuild SDK Support for AWS codebuild
aws_targets_codecommit SDK Support for AWS codecommit
aws_targets_codedeploy SDK Support for AWS codedeploy
aws_targets_codepipeline SDK Support for AWS codepipeline
aws_targets_codestar SDK Support for AWS codestar
aws_targets_cognito-identity SDK Support for AWS cognito-identity
aws_targets_cognito-idp SDK Support for AWS cognito-idp
aws_targets_cognito-sync SDK Support for AWS cognito-sync
aws_targets_comprehend SDK Support for AWS comprehend
aws_targets_config SDK Support for AWS config
aws_targets_connect SDK Support for AWS connect
aws_targets_core SDK Support for AWS core
aws_targets_cur SDK Support for AWS cur
aws_targets_datapipeline SDK Support for AWS datapipeline
aws_targets_dax SDK Support for AWS dax
aws_targets_devicefarm SDK Support for AWS devicefarm
aws_targets_directconnect SDK Support for AWS directconnect
aws_targets_discovery SDK Support for AWS discovery
aws_targets_dms SDK Support for AWS dms
aws_targets_ds SDK Support for AWS ds
aws_targets_dynamodb SDK Support for AWS dynamodb
aws_targets_dynamodbstreams SDK Support for AWS dynamodbstreams
aws_targets_ec2 SDK Support for AWS ec2
aws_targets_ecr SDK Support for AWS ecr
aws_targets_ecs SDK Support for AWS ecs
aws_targets_eks SDK Support for AWS eks
aws_targets_elasticache SDK Support for AWS elasticache
aws_targets_elasticbeanstalk SDK Support for AWS elasticbeanstalk
aws_targets_elasticfilesystem SDK Support for AWS elasticfilesystem
aws_targets_elasticloadbalancing SDK Support for AWS elasticloadbalancing
aws_targets_elasticloadbalancingv2 SDK Support for AWS elasticloadbalancingv2
aws_targets_elasticmapreduce SDK Support for AWS elasticmapreduce
aws_targets_elastictranscoder SDK Support for AWS elastictranscoder
aws_targets_email SDK Support for AWS email
aws_targets_es SDK Support for AWS es
aws_targets_events SDK Support for AWS events
aws_targets_firehose SDK Support for AWS firehose
aws_targets_fms SDK Support for AWS fms
aws_targets_gamelift SDK Support for AWS gamelift
aws_targets_glacier SDK Support for AWS glacier
aws_targets_glue SDK Support for AWS glue
aws_targets_greengrass SDK Support for AWS greengrass
aws_targets_guardduty SDK Support for AWS guardduty
aws_targets_health SDK Support for AWS health
aws_targets_iam SDK Support for AWS iam
aws_targets_identity-management SDK Support for AWS identity-management
aws_targets_importexport SDK Support for AWS importexport
aws_targets_inspector SDK Support for AWS inspector
aws_targets_iot SDK Support for AWS iot
aws_targets_iot-data SDK Support for AWS iot-data
aws_targets_iot-jobs-data SDK Support for AWS iot-jobs-data
aws_targets_iot1click-devices SDK Support for AWS iot1click-devices
aws_targets_iot1click-projects SDK Support for AWS iot1click-projects
aws_targets_iotanalytics SDK Support for AWS iotanalytics
aws_targets_kinesis SDK Support for AWS kinesis
aws_targets_kinesis-video-archived-media SDK Support for AWS kinesis-video-archived-media
aws_targets_kinesis-video-media SDK Support for AWS kinesis-video-media
aws_targets_kinesisanalytics SDK Support for AWS kinesisanalytics
aws_targets_kinesisvideo SDK Support for AWS kinesisvideo
aws_targets_kms SDK Support for AWS kms
aws_targets_lambda SDK Support for AWS lambda
aws_targets_lex SDK Support for AWS lex
aws_targets_lex-models SDK Support for AWS lex-models
aws_targets_lightsail SDK Support for AWS lightsail
aws_targets_logs SDK Support for AWS logs
aws_targets_machinelearning SDK Support for AWS machinelearning
aws_targets_macie SDK Support for AWS macie
aws_targets_marketplace-entitlement SDK Support for AWS marketplace-entitlement
aws_targets_marketplacecommerceanalytics SDK Support for AWS marketplacecommerceanalytics
aws_targets_mediaconvert SDK Support for AWS mediaconvert
aws_targets_medialive SDK Support for AWS medialive
aws_targets_mediapackage SDK Support for AWS mediapackage
aws_targets_mediastore SDK Support for AWS mediastore
aws_targets_mediastore-data SDK Support for AWS mediastore-data
aws_targets_mediatailor SDK Support for AWS mediatailor
aws_targets_meteringmarketplace SDK Support for AWS meteringmarketplace
aws_targets_mobile SDK Support for AWS mobile
aws_targets_mobileanalytics SDK Support for AWS mobileanalytics
aws_targets_monitoring SDK Support for AWS monitoring
aws_targets_mq SDK Support for AWS mq
aws_targets_mturk-requester SDK Support for AWS mturk-requester
aws_targets_neptune SDK Support for AWS neptune
aws_targets_opsworks SDK Support for AWS opsworks
aws_targets_opsworkscm SDK Support for AWS opsworkscm
aws_targets_organizations SDK Support for AWS organizations
aws_targets_pi SDK Support for AWS pi
aws_targets_pinpoint SDK Support for AWS pinpoint
aws_targets_polly SDK Support for AWS polly
aws_targets_pricing SDK Support for AWS pricing
aws_targets_queues SDK Support for AWS queues
aws_targets_rds SDK Support for AWS rds
aws_targets_redshift SDK Support for AWS redshift
aws_targets_rekognition SDK Support for AWS rekognition
aws_targets_resource-groups SDK Support for AWS resource-groups
aws_targets_resourcegroupstaggingapi SDK Support for AWS resourcegroupstaggingapi
aws_targets_route53 SDK Support for AWS route53
aws_targets_route53domains SDK Support for AWS route53domains
aws_targets_s3 SDK Support for AWS s3
aws_targets_s3-encryption SDK Support for AWS s3-encryption
aws_targets_sagemaker SDK Support for AWS sagemaker
aws_targets_sagemaker-runtime SDK Support for AWS sagemaker-runtime
aws_targets_sdb SDK Support for AWS sdb
aws_targets_secretsmanager SDK Support for AWS secretsmanager
aws_targets_serverlessrepo SDK Support for AWS serverlessrepo
aws_targets_servicecatalog SDK Support for AWS servicecatalog
aws_targets_servicediscovery SDK Support for AWS servicediscovery
aws_targets_shield SDK Support for AWS shield
aws_targets_sms SDK Support for AWS sms
aws_targets_snowball SDK Support for AWS snowball
aws_targets_sns SDK Support for AWS sns
aws_targets_sqs SDK Support for AWS sqs
aws_targets_ssm SDK Support for AWS ssm
aws_targets_states SDK Support for AWS states
aws_targets_storagegateway SDK Support for AWS storagegateway
aws_targets_sts SDK Support for AWS sts
aws_targets_support SDK Support for AWS support
aws_targets_swf SDK Support for AWS swf
aws_targets_text-to-speech SDK Support for AWS text-to-speech
aws_targets_transcribe SDK Support for AWS transcribe
aws_targets_transfer SDK Support for AWS transfer
aws_targets_translate SDK Support for AWS translate
aws_targets_waf SDK Support for AWS waf
aws_targets_waf-regional SDK Support for AWS waf-regional
aws_targets_workdocs SDK Support for AWS workdocs
aws_targets_workmail SDK Support for AWS workmail
aws_targets_workspaces SDK Support for AWS workspaces
aws_targets_xray SDK Support for AWS xray

beignet

ocl-icd Enable compatibility with the dev-libs/ocl-icd OpenCL ICD loader
ocl20 Enable experimental OpenCL 2.0 support on Skylake and newer architectures

bitset

tcmalloc Use tcmalloc from dev-util/google-perftools for allocations

blitz

boost Enable usage of boost::serialization

boost

context Build and install the Boost.Context (and Boost.Fiber) library and all other Boost libraries that depend on it
debug Build and install only the debug version of the Boost libraries. Only enable this flag if you're developing against boost.
doc Install the full API documentation documentation. This takes over 200MB of extra disk space.
nls Build libboost_locale. This library requires compatible C library interfaces, which might not be provided by uClibc or other embedded libraries.
threads Build multi-thread-compatible libraries instead of single-threaded only.
tools Build and install the boost tools (bcp, quickbook, inspect, wave)

botan

boost use dev-libs/boost

c-blosc

lz4 Enable lz4 compression
snappy Enable snappy compression
zstd Enable zstd compression

check

subunit Enable support for the subunit unit test protocol

crypto++

asm Support assembly hand optimized crypto functions (i.e. faster run time)

cyberjack

tools Build and install optional management tools.
usb Enable support for usb based chipcard reader.

cyrus-sasl

authdaemond Add Courier-IMAP authdaemond unix socket support (net-mail/courier-imap, mail-mta/courier)
ldapdb Enable ldapdb plugin
openldap Add ldap support for saslauthd
sample Enable sample client and server
srp Enable SRP authentication
urandom Use /dev/urandom instead of /dev/random

dbus-c++

ecore Use Ecore integration
glib Use glib integration

eekboard

libcanberra Enable support for media-libs/libcanberra
xtest Enable support for x11-libs/libXtst

efl

bmp Enable WBMP image loader
dds Enable DDS image loader
drm Enable DRM engine
eet Enable Eet image loader
egl Enable EGL rendering
fribidi Enable bidirectional text support
gles Enable the OpenGL ES GL implementation
glib Enable dev-libs/glib support
harfbuzz Enable complex text shaping and layout support
hyphen Enable text hyphenation support
ibus Enable Intelligent Input Bus
ico Enable Ico image loader
ivi Enable ivi-shell support
libuv Enable dev-libs/libuv support
luajit USE dev-lang/luajit instead of dev-lang/lua
physics Enable Bullet physics effects and support
pixman Enable PixMan for software rendering
ppm Enable PMAPS image loader
psd Enable PSD image loader
scim Enable Smart Common Input Method
system-lz4 Use system liblz4 instead of bundled one
tga Enable Tga image loader
tslib Enable x11-libs/tslib for touchscreen events
unwind Enable debug support via sys-libs/libunwind
valgrind Enable usage of dev-util/valgrind in debug
vlc Enable media-video/vlc support
xcf Enable XCF image loader
xim Enable X Input Method
xpresent Enable x11-libs/libXpresent support

elfutils

lzma Support automatic decompression of LZMA-compressed files and kernel images
threads Build the libraries with thread safe support
utils Install command-line utilities (all the eu-* programs)

ell

glib Enable dev-libs/glib support

fcgi

html Install HTML documentation

folks

telepathy Load contacts from the Telepathy framework
tracker Load contacts from app-misc/tracker index
utils Build the folks-inspect utility

fstrm

utils Build fstrm utility programs

gecode

gist Enable Gist, the Gecode Interactive Search Tool
gmp Enable trigonometric and transcendental float constraints

gf2x

bindist Disable automatic fine-tuning to local processor features like pclmul or sse2.
custom-tune Extra long compile time for tuning hardware specific low-level routines
fft Build an FFT API for multiplication of 2 polynomials over GF(2)

glib

dbus Enable dependencies required by glib libraries using dbus service to manage settings saving
mime Pull in shared MIME database that many glib-based applications require at runtime to detect or open files. Warning: do not disable this flag unless installing on a headless server.
systemtap Build support for profiling and tracing using dev-util/systemtap
utils Install gtester-report utility to generate test report files for your software; build gresource utility with ELF support.

gmime

smime Enable experimental S/MIME support

gmp

asm Enable use of hand optimized assembly routines (faster execution)
pgo After building gmp, run some tests against to produce faster libraries -- this option will double the compile time

gobject-introspection

doctool Install g-ir-doc-tool for generating documentation from introspected data

granite

demo Build the Granite demo application (to present all available UI features provided by the library)

hidapi

fox Build a x11-libs/fox GUI

input-pad

eekboard Enable support for dev-libs/eekboard
xtest Enable support for x11-libs/libXtst

jemalloc

hugepages Enable transparent huge page support
lazy-lock Enable lazy locking (only lock when multi-threaded)
stats Enable statistics calculation/reporting
xmalloc Add support for xmalloc (abort-on-out-of-memory)

kreport

marble Enable displaying of maps using kde-apps/marble
scripting Support Qml scripting using dev-qt/qtdeclarative

leveldb

snappy support the snappy compression library

libbase58

tools Build command line base58 tool

libcdio

minimal Only build the libcdio library and little more, just to be used to link against from multimedia players. With this USE flag enabled, none of the command-line utilities are built, nor is the CDDA library.

libcec

cubox Enable support for enable support for the TDA995x
exynos Enable support for Exynos chipsets
raspberry-pi Enable support for the Raspberry Pi
xrandr Enable detection of active HDMI using xrandr extensions

libcgroup

daemon Install the configuration tools and init/config files.
tools Install the cgroup rules processing daemon and init/config files.

libclsync

extra-debug Enable extra debugging. This will hurt performance badly. Be ready for tons of output.
extra-hardened Enable extra security checks. This may hurt performance.

libdbusmenu

gtk Enable support for GTK+2
gtk3 Enable support for GTK+3

libdivecomputer

tools Install tools that can be used to test the library.

libdynd

cuda Enable NVIDIA CUDA toolkit support
mkl Enable a plugin for Intel Math Kernel Library sci-libs/mkl

libevent

debug Support runtime debug mode and malloc hooks (for programmers)

libffi

pax_kernel Use PaX emulated trampolines, for we can't use PROT_EXEC

libflatarray

cuda Enables plugins for NVIDIA GPUs (e.g. CUDAAllocator)

libgcrypt

o-flag-munging Enable O-flag mangling during build

libgdata

gnome-online-accounts Enable net-libs/gnome-online-accounts support

libgit2

curl Use net-misc/curl for HTTP support (otherwise, limited built-in implementation will be used)
gssapi Enable GSSAPI support for SPNEGO auth
ssh Enable SSH transport support
trace Enable tracing support

libgit2-glib

ssh Enable SSH transport support

libgpg-error

common-lisp Install common-lisp files

libgpiod

tools Build some useful gpio tools that use libgpiod.

libgpuarray

cuda Enable NVIDIA CUDA toolkit support
opencl Enable OpenCL support

libgweather

glade Installs catalog files for dev-util/glade

libisoburn

external-filters Allow the use of external processes as file content filters (Note: this is a potential security risk)
external-filters-setuid Also allow the use of external setuid processes as file content filters (Note: this is a potential security risk)
frontend-optional Use dev-tcltk/bwidget which is not strictly required for the frontend
launch-frontend Enable the tcl gui for xorriso
launch-frontend-setuid Enable the tcl gui for xorriso under setuid

libisofs

verbose-debug Enable verbose debug messages

liblogging

rfc3195 Enables RFC 3195 protocol (aka syslog-reliable) support. If you don't know what this is, you don't need it!
stdlog Enables liblogging's core component (think of it as a the next version of the syslog(3) API).

libmail

apop Enables the APOP authentication method

libmemcached

hsieh Use Hsieh hash algorithm.
libevent Use the libevent event loop interface.
sasl Use sasl auth for communications.

libmspack

utils Enables building cabrip, chmextract, msexpand and oabextract

libnfc

pcsc-lite Enable NFC drivers that require pcsc-lite

libnl

doc Install development documentation
python Install experimental dev-lang/python bindings
utils Install command line interface utils

liborcus

spreadsheet-model Enable the spreadsheet model implementation
tools Build various low-level parsers

libowfat

diet Compile against dev-libs/dietlibc

libp11

doc Generate and install API documentation for the package.

libpcre

bzip2 Add support for pcregrep command to search within bzip2-compressed files (via app-arch/bzip2).
pcre16 Build PCRE library for 16 bit characters (e.g. UTF-16).
pcre32 Build PCRE library for 32 bit characters (e.g. UTF-32).
readline Add support for command line editing to pcretest, through sys-libs/readline.
recursion-limit Limit match recursion to 8192; if disabled, the default limit is used, which is the same as the match limit.
zlib Add support for pcregrep command to search within gzip-compressed files (via sys-libs/zlib).

libpcre2

bzip2 Add support for pcregrep command to search within bzip2-compressed files (via app-arch/bzip2).
pcre16 Build PCRE library for 16 bit characters (e.g. UTF-16).
pcre32 Build PCRE library for 32 bit characters (e.g. UTF-32).
readline Add support for command line editing to pcretest, through sys-libs/readline.
recursion-limit Limit match recursion to 8192; if disabled, the default limit is used, which is the same as the match limit.
zlib Add support for pcregrep command to search within gzip-compressed files (via sys-libs/zlib).

libpeas

glade Install the glade catalog
python Build support for loading dev-lang/python plugins

librdkafka

lz4 Enable support for Kafka's LZ4 compression based on KIP-57 (uses app-arch/lz4)

librelp

gnutls Use GnuTLS
libressl Use LibreSSL
openssl Use OpenSSL

libressl

asm Enables assembly

libsecp256k1

asm Enable x86_64 assembly optimisation
ecdh Enable ECDH shared secret computation
endomorphism Enable endomorphism
experimental Allow experimental USE flags
recovery Enable ECDSA pubkey recovery module
schnorr Enable Schnorr signature module
test_openssl Enable OpenSSL comparison tests

libslz

tools Install additional tools (zenc, zdec)

libsodium

asm Enables assembly implementations
urandom Use /dev/urandom instead of /dev/random

libsolv

rpm Enable support for RPM files

libspt

libtirpc Build against net-libs/libtirpc for RPC support

libsqlora8

orathreads Use Oracle threads

libtasn1

valgrind Enable usage of dev-util/valgrind in debug

libtermkey

demos Install demos, which pulls in dev-libs/glib

libucl

regex Enable regex checking for schema
signatures Enable signatures check
urlfetch Enable URLs fetch
utils Install the chargen and objdump utilities

libunibreak

doc Install html API documentation.
man Generate man pages with doxygen.

libverto

glib Support event loops using dev-libs/glib
libev Support event loops using dev-libs/libev
libevent Support event loops using dev-libs/libevent
tevent Support event loops using sys-libs/tevent

libxmlb

stemmer Enable language stemming support

libzia

ftdi Enable support for FTDI USB chips
aspell Adds support for app-text/aspell spell checker
hunspell Adds support for app-text/hunspell spell checker

log4cplus

iconv Use inconv for wchar_t <-> char conversions. See also log4cplus's unicode.txt documentation
working-c-locale Use the C99 locale facilities for wchar_t <-> char conversions. See also log4cplus's unicode.txt documentation
working-locale Use C++'s std::locale for wchar_t <-> char conversions. See also log4cplus's unicode.txt documentation

log4cxx

smtp Offer SMTP support via net-libs/libesmtp

m17n-lib

X Build the Graphical User Interface API and utilities
anthy Enable support for app-i18n/anthy input method
athena Enable the MIT Athena widget set (x11-libs/libXaw)
gd Build API and utilities based on media-libs/gd. This flag is only meaningful if the X USE flag is also enabled
libotf Use dev-libs/libotf to handle OpenType fonts
libxml2 Use dev-libs/libxml2 to parse XML

nss

cacert Include root/class3 certs from CAcert (http://www.cacert.org/)
nss-pem Add support for libnsspem
utils Install utilities included with the library

ocl-icd

khronos-headers Install Khronos OpenCL headers.

onigmo

combination-explosion-check enable combination explosion check
crnl-as-line-terminator enable CR+NL as line terminator

oniguruma

crnl-as-line-terminator enable CR+NL as line terminator

opencryptoki

tpm Enable support for Trusted Platform Module (TPM) using app-crypt/trousers

openct

debug Add debug output to the driver library for pcsc-lite.
pcsc-lite Build a driver library for sys-apps/pcsc-lite, providing PC/SC API access to devices supported by OpenCT.

openobex

irda Enable IrDA support

opensc

ctapi Use CT-API for accessing Smartcard hardware
notify Enable notifications
openct Use dev-libs/openct (and CT-API) for accessing Smartcard hardware
pcsc-lite Use sys-apps/pcsc-lite (and PC/SC API) for accessing Smartcard hardware
secure-messaging Enable secure messaging

openssl

asm Support assembly hand optimized crypto functions (i.e. faster run time)
bindist Disable/Restrict EC algorithms (as they seem to be patented) -- note: changes the ABI
rfc3779 Enable support for RFC 3779 (X.509 Extensions for IP Addresses and AS Identifiers)
sslv2 Support for the old/insecure SSLv2 protocol -- note: not required for TLS/https
sslv3 Support for the old/insecure SSLv3 protocol -- note: not required for TLS/https
tls-heartbeat Enable the Heartbeat Extension in TLS and DTLS

pkcs11-helper

nss Enable NSS crypto engine

poco

7z Add Support for the 7z archive format
apache Enable support to write Apache modules using POCO
cppparser Build and install a minimal C++ parser
crypto Encryption and digital signing classes
data Database abstraction layer to easily send/retrieve data to/from various databases
file2pagecompiler Utility to convert ordinary files to Page Compiler source files
json Add JSON support
mongodb Add dev-db/mongodb support
net Classes to write network clients & servers
pagecompiler Simple compiler translating HTML pages containing embedded C++ code into HTTPRequestHandler classes
pocodoc POCO documentation generator
util Several utility classes (like logger, timer, config file parser)
zip Add support for the zip & gz archive formats

ppl

lpsol Build the ppl_lpsol linear programming problem solver

serdisplib

tools Build optional tools.

softhsm

migration-tool Build db migration tool

starpu

cuda Enable NVIDIA CUDA toolkit support
gcc-plugin Enable GCC extension plugin (experimental)
opencl Enable OpenCL support
spinlock-check Enable spinlock check
valgrind Enable dev-util/valgrind support

sway

X Enable support for X11 applications (XWayland)
elogind Enable support for rootless session via elogind
filecaps Use Linux capability SYS_CAP_ADMIN rather than set*id for sway binary
fish-completion Enable fish completion support
gdk-pixbuf Enable additional image format support via the x11-libs/gdk-pixbuf library
swaybar Install 'swaybar': sway's status bar component
swaybg Install 'swaybg': allows to set a desktop background image
swaygrab Install 'swaygrab': allows taking screenshots or screencasts
swaylock Install 'swaylock': sway's screen locker
swaymsg Install 'swaymsg': tool for communicating with a running sway instance
tray Enable support for StatusNotifierItem tray specification
wallpapers Install sway's default wallpaper image

tinyxml

stl Compile with TIXML_USE_STL support

tntnet

server Enable tntnet server daemon

totem-pl-parser

archive Enables support for accessing media files in archives transparently via app-arch/libarchive
quvi Use media-libs/libquvi for parsing video links

tvision

gpm Support text mode mouse through sys-libs/gpm

ucommon

socks Build with socks proxy support

userspace-rcu

regression-test Run regression tests (requires FEATURES=test)

ustr

ustr-import Install ustr-import developer program and source code for bundling.

weston

colord Allow setting color managment
drm Enable drm compositor support
editor Install wayland-editor example application
fbdev Enable fbdev compositor support
gles2 Use GLESv2 cairo instead of full GL
headless Headless backend and a noop renderer, mainly for testing purposes
ivi Enable the IVI shell
launch Install weston-launch utility
rdp Enable Remote Desktop Protocol compositor support
remoting Enable plugin to stream output to remote hosts using media-libs/gstreamer
resize-optimization Increase performance, allocate more RAM. Recommended to disable on Raspberry Pi
screen-sharing Enable screen-sharing through RDP
unwind Enable libunwind usage for backtraces
wayland-compositor Enable Wayland compositor support
xwayland Enable ability support native X11 applications

wlc

X Enable X11 backend.
systemd Enable support for systemd-logind.
xwayland Enable XWayland application support.

wlroots

X Enable support for X11 applications (XWayland)
elogind Enable support for rootless session via elogind
icccm Use xcb-icccm (from x11-libs/xcb-util-wm) util library for improved Xwayland introspection
rootston Build the rootston example compositor
x11-backend Enable support for handling input/output devices through x11-libs/libxcb

xapian

brass Enabled brass backend db support
chert Enabled chert backend db support
glass Enabled glass backend db support
inmemory Enabled inmemory backend db support

xerces-c

iconv Use iconv (virtual/libiconv) as message loader and transcoder (in general it would be possible to use iconv only as message loader and something else like icu or the native method as transcoder and vice-versa, but this is a less common case and hard to handle)
threads Enable threading support through pthread (or other libraries on AIX, IRIX, HPUX, Solars). Highly recommended

xml-security-c

nss Use dev-libs/nss for certain crypto operations (configureable at runtime)
xalan Enable support for XSLT and XPath parsing by dev-libs/xalan-c

xmlrpc-c

abyss Build the Abyss mini web-server.
libxml2 Use dev-libs/libxml2 to parse XML instead of the internal expat library.
threads Controls whether to build the Abyss web-server with pthreads or fork 'threading'.
tools Build the xmlrpc* tools.

xmlsec

gcrypt Install xmlsec-gcrypt library
gnutls Install xmlsec-gnutls library
nss Install xmlsec-nss library
openssl Install xmlsec-openssl library

xqilla

faxpp Use dev-libs/faxpp instead of Xerces-C for certain tasks
htmltidy Use app-text/htmltidy when parsing HTML

yaz

ziffy Install ziffy, a promiscuous Z39.50 APDU sniffer

dev-lisp

clisp

hyperspec Use local hyperspec instead of online version
new-clx Build CLISP with support for the NEW-CLX module which is a -C binding to the Xorg libraries
svm Build CLISP with support for the Support Vector Machine module

clx

doc Builds documentation

cmucl

X Build CLX, CLM, or Hemlock
doc Installs package documentation
source Include source code for CMUCL in installation

ecls

gengc Use generational garbage collection (experimental)
libatomic Use dev-libs/libatomic_ops library
precisegc Use type information during garbage collection (experimental)

gcl

ansi Build a GCL with ANSI support (else build a traditional CLtL1 image)
athena Build xgcl - an interface to x11-libs/libXaw

sbcl

pax_kernel Enable if the user plans to run the package under a pax enabled hardened kernel

dev-lua

luarocks

curl Uses net-misc/curl for fetching lua packages instead of net-misc/wget.
openssl Uses dev-libs/openssl for verifying lua packages instead of md5sum.

luvit

bundled-libs Use bundled versions of some libraries.

dev-ml

cairo-ocaml

pango Enable support for x11-libs/pango

csv

lwt Enables the Lwt-based library for asynchronous operations.

dose3

parmap Adds multi-core CPU support via dev-ml/parmap.
rpm4 Adds support for handling rpm4 files.
zip Adds support for handling zip files.

eliom

ppx Enable PPX syntax extension support.

js_of_ocaml

camlp4 Build with camlp4 syntax extensions.
deriving Enable dev-ml/deriving support for improving the type safety.
lwt Enable dev-ml/lwt support.
ppx Enables the ppx syntax extension
react Enable functionnal reactive programming support.

lablgtk

glade Enable libglade bindings compilation.
gnomecanvas Enable libgnomecanvas bindings compilation.
sourceview Enable GtkSourceView support

logs

cli Enables the Logs_cli library that provides command line support for controlling Logs.
fmt Enables the Logs_fmt reporter.
lwt Enables the Logs_lwt library that provides Lwt logging functions.

lwt

camlp4 Enable camlp4 syntax extension
libev Enable the dev-libs/libev-based backend.
ppx Enables the ppx syntax extension

ocaml-cohttp

async Enables support for the dev-ml/async asynchronous execution library.
lwt Enables support for the dev-ml/lwt cooperative light-weight thread library.

ocaml-cstruct

async Support for asynchronous execution
lwt Enable threads via lwt
ppx Enable the ppx syntax extension

ocaml-websocket

async Enables support for the dev-ml/async asynchronous execution library.
lwt Enables support for the dev-ml/lwt cooperative light-weight thread library.

ocamlnet

httpd Enables net-httpd web server component
zip Enables netzip support to read/write gzip data using object channels

onanomsg

lwt Enables lwt support.

pgocaml

camlp4 Enable PG'Ocaml syntax extension.

tyxml

camlp4 Enables the camlp4 syntax extension (deprecated)
ppx Enables the ppx syntax extension (preferred)

uutf

utftrip Builds and install the utftrip executable: Among other things, reads unicode on stdin and rewrites it on stdout.

zarith

mpir Use MPIR library instead of GMP.

dev-perl

App-Nopaste

browser Spawn browser with pasted page
clipboard copying of URLs with -x/--copy
github Github authentication
gitlab Ensure git is installed for reading/passing GitLab authentication
pastebin pastebin.com support

Business-ISBN

barcode Install dev-perl/GD-Barcode for rendering ISBN numbers as barcodes

Config-Any

conf Install dev-perl/Config-General to support decoding .conf/.cnf files
ini Install dev-perl/Config-Tiny to support decoding INI config files
json Install support libraries to support decoding JSON config files
xml Install support libraries to support decoding XML config files
yaml Install support libraries to support decoding YAML config files

Convert-UUlib

system-uulib Use dev-libs/uulib instead of bundled version.

Cookie-Baker

xs Install dev-perl/Cookie-Baker-XS for accelerated performance

Coro

ev Build support for using dev-perl/EV as an event-loop via Coro::EV
event Build support for using dev-perl/Event as an event-loop via Coro::Event

DBD-SQLite

system-sqlite Use the system-wide dev-db/sqlite installation

DBD-mysql

embedded Support embedded server (libmysqld)
ssl Compile in support for SSL connections via libmysqlclient

DBIx-Class

admin Modules required for the DBIx::Class administrative library
admin_script Modules required for the CLI DBIx::Class interface dbicadmin
deploy Modules required for "deploy" in DBIx::Class::Storage::DBI and "deploymen_statements" in DBIx::Class::Storage::DBI
replicated Modules required for DBIx::Class::Storage::DBI::Replicated

File-HomeDir

xdg Ensure XDG Semantics for returned paths via x11-misc/xdg-user-dirs

File-Which

pwhich Install dev-perl/App-pwhich which used to be a part of this package

GD

animgif Enable animated gif support
fcgi Build for FastCGI compatibility via dev-libs/fcgi instead of using PerlIO

Graphics-ColorNames

recommended Install recommended support modules

HTML-Mason

modperl Enable www-apache/mod_perl support

HTTP-Entity-Parser

xs Install C-Based dependieces for faster performance

JSON

xs Install C-based dev-perl/JSON-XS for faster performance

JSON-MaybeXS

xs Install a C-Based backend to make JSON encode/decode fast

Lab-VXI11

libtirpc Build against net-libs/libtirpc for RPC support

List-MoreUtils

xs Install C-Based backend implementation for performance

MCE

sereal Install dev-perl/Sereal-Encoder and decoder for faster worker IPC

Mail-IMAPClient

md5 Install support for DIGEST-MD5 and CRAM-MD5 Authentication
ntlm Install support for NTLM Authentication
ssl Install support for SSL Connections
zlib Install support for COMPRESS DEFLATE connections

Net-SSH2

gcrypt Use libgcrypt instead of openssl

PDL

badval Enable bad values support
hdf Enable HDF (version 4) format support
netpbm Enable NETPBM and MPEG support
pdl2 Build pdf2 shell (requires Devel-REPL)
pgplot Enable PGPLOT plotting capabilities

Panotools-Script

gui Installs GUIs for some tools

Ref-Util

xs Install C-Based dev-perl/Ref-Util-XS for accelerated performance

Sub-Name

suggested Install extra dependencies needed for extended regression tests

Sysadm-Install

hammer Enable hammer() funtion to run a command in the shell and simulate a user hammering the ENTER key to accept defaults on prompts

Test-Warnings

suggested Install optional dependencies for extra tests

Text-CSV

xs Install dev-perl/Text-CSV_XS for accelerated decoding

WWW-Form-UrlEncoded

xs Install C-Based dependieces for faster performance

perl-headers

debug Add source locations in generated .ph files to assist with debugging when errors occur
sizeof-warning Include logic to warn when a .ph file tries to use a sizeof() that is unknown

dev-php

PEAR-HTTP_Request2

curl Force dev-lang/php to be compiled with curl extension
fileinfo Force dev-lang/php to be compiled with fileinfo extension
ssl Force dev-lang/php to be compiled with ssl extension
zlib Force dev-lang/php to be compiled with zlib extension

PEAR-PHP_Beautifier

cli Require dev-lang/php to be built with the "cli" SAPI and install the php_beautifier script.

agavi

executable Install the "agavi" executable used to manage projects. This requires dev-php/phing, and may be omitted if you are (for example) deploying an existing site to a production server.

maxmind-db-reader

extension Build the C extension that uses dev-libs/libmaxminddb

pecl-apcu

lock_pthreadmutex Enable pthread mutex locking
lock_pthreadrw Enable pthread read/write locking
lock_semaphore Enable semaphore locks instead of fcntl
lock_spinlock Enable spin locks (EXPERIMENTAL)

pecl-event

extra Add support of the Libevent extra API

pecl-memcached

igbinary Enable support for the igbinary serializer
json Enable support for json serialization

pecl-mysqlnd_qc

memcached Use dev-libs/libmemcached as a storage handler
sqlite Use dev-db/sqlite as a storage handler

pecl-redis

igbinary Enables igbinary serialisation support

pecl-zmq

czmq Use the czmq high level bindings

phing

zip Support zip archives by requiring said support in dev-lang/php.

swoole

http2 Add support for HTTP/2 protocol via net-libs/nghttp2
redis Add support for redis via dev-libs/hiredis

twig

extension Build the C extension (only for php-5.6.x).

xcache

coverage Enable the coverager module (not recommended for production servers).

dev-python

Kivy

camera Install libraries needed to support camera
garden Install garden tool to manage user maintained widgets

PyQt5

bluetooth Build bindings for the QtBluetooth module
dbus Build bindings for the QtDBus module
declarative Build bindings for the QtQml/QtQuick modules and enable the qmlscene plugin
designer Build bindings for the QtDesigner module and enable the designer plugin
gles2 Use GLES 2.0 or later instead of full OpenGL
gui Build bindings for the QtGui module
help Build bindings for the QtHelp module
location Build bindings for the QtLocation module
multimedia Build bindings for the QtMultimedia module
network Build bindings for the QtNetwork module
opengl Build bindings for the QtOpenGL module
positioning Build bindings for the QtPositioning module
printsupport Build bindings for the QtPrintSupport module
sensors Build bindings for the QtSensors module
serialport Build bindings for the QtSerialPort module
sql Build bindings for the QtSql module
svg Build bindings for the QtSvg module
testlib Build bindings for the QtTest module
webchannel Build bindings for the QtWebChannel module
webengine Build bindings for the QtWebEngine module
webkit Build bindings for the QtWebKit module
websockets Build bindings for the QtWebSockets module
widgets Build bindings for the QtWidgets module
x11extras Build bindings for the QtX11Extras module
xmlpatterns Build bindings for the QtXmlPatterns module

PythonQt

extensions Install extensions

QtPy

designer Build bindings for the QtDesigner module and enable the designer plugin
gui Build bindings for the QtGui module
svg Build bindings for the QtSvg module
testlib Build bindings for the QtTest module
webengine Build bindings for the QtWebEngine module
webkit Build bindings for the QtWebKit module

amqplib

extras Install extra tools to generate initial Python mod from an AMQP XML file

anyvc

bazaar Add support for Bazaar
mercurial Add support for Mercurial

celery

redis Enables redis support
sqs Enables Amazon SQS transport module for celery
yaml Enable support of yaml as a configuration file format

cgkit

3ds Enable support for importing 3D Studio models

cvxopt

dsdp Use interior point library sci-libs/dsdp
glpk Use GNU Linear Programming Kit sci-mathematics/glpk

dap

server Enable OpenDAP server support

dask

distributed Add support for distributed computing with dev-python/distributed

django-cms

admin-style Install plugin customizing admin panel styles
ckeditor Install text-ckeditor plugin for rich text editing
file Install djangocms file plugin
flash Install djangocms flash plugin
inherit Install djangocms inherit plugin
link Install djangocms link plugin
picture Install djangocms picture plugin
snippet Install djangocms snippet plugin
teaser Install djangocms teaser plugin
video Install djangocms video plugin

editorconfig-core-py

cli Install command line interface as well as python library

fabric

fab2 Install as "fab2", allowing side-by-side install with fabric 1.x

falcon

cython Build cython-based python modules

fastparquet

brotli Enable support for brotli compression
lz4 Enable support for lz4 compression
snappy Enable support for snappy compression
zstd Enable support for zstandard compression

flask-restful

paging Enable resource paging support

geopy

timezone Enables localized date support
yahoo Enables use of YahooPlaceFinder

glance_store

cinder enable cinder backend supprt
swift enable swift backend supprt
vmware enable vmware backend supprt

gmpy

mpir Use sci-libs/mpir as gmp implementation

icalendar

doc Generate examples and other extra documentation

ipython

matplotlib Add support for dev-python/matplotlib
nbconvert Enable support for converting notebooks to various formats using app-text/pandoc
notebook Install requirements for the web notebook based on www-servers/tornado

jira

filemagic Include filemagic support (for identifying uploaded filetypes)
ipython Include Interactive Python (IPython)
jirashell Include dependencies for jirashell (ipython, oauthlib)
kerberos Support Kerberos authentication
oauth Support OAuth authentication

kaa-base

tls SSL/TLS support via dev-python/tlslite

kafka-python

snappy Install snappy compression/decompression support

kazoo

gevent Enable support for the gevent based handler

kombu

mongodb Enables MongoDB backend
msgpack Enables MessagePack (de)serializer for Python
redis Enables Redis backend
sqs Enables Amazon SQS transport module for Kombu
yaml Enables yaml backend

markdown

pygments Enable fancy pygments support

matplotlib

excel Pull dev-python/xlwt for the exceltools toolkit
gtk2 Enable x11-libs/gtk+:2 support
gtk3 Enable x11-libs/gtk+:3 support

mpmath

matplotlib Add support for dev-python/matplotlib

msgpack

native-extensions Compiles native "C" extensions (speedups, instead of using python fallback code).

nbdime

webtools Install web-based diff and merge tools.

netaddr

cli Enable netaddr shell with dev-python/ipython

networkx

extras Provide graph drawing and graph layout algorithms along with shapefile format reading and writing
pandas Provides a DataFrame, which is a tabular data structure with labeled axes
scipy Enables scipy backend
yaml Provides YAML format reading and writing

nltk

numpy Use numpy for the saved word tokenizer

numexpr

mkl Enable support for Intel Vector Math Library, part of sci-libs/mkl.

pandas

full-support Pull all packages to give pandas full support

paramiko

server Enable server feature

passlib

bcrypt bcrpyt hash algoryptm support
scrypt accelerated scrypt algoythm support
totp time based one time password support

paste

flup enable support for flup (and therefore for various wgsi servers and middleware)
openid enable OpenID support

pillow

imagequant Build with Image Quantization Library support

py-amqp

extras Install extra tools to generate initial Python mod from an AMQP XML file

pygame

midi Enable midi support using media-libs/portmidi

pygpu

cuda Enable NVIDIA CUDA toolkit support
opencl Enable OpenCL support

pyilmbase

numpy Add bindings for dev-python/numpy use.

pyocr

cuneiform Enable support for the app-text/cuneiform OCR engine
tesseract Enable support for the app-text/tesseract OCR engine

pypax

ptpax Enable PT_PAX_FLAGS support.
xtpax Enable XATTR_PAX_FLAGS support.

pyplusplus

indexing Install indexing_suite_v2 to enhance boost python
numpy Generate code for dev-libs/boost-numpy to accelerate arrays

pypy

low-memory Build using PyPy with the engine configured towards low memory footprint. This makes it possible to build PyPy using ~3.5G of RAM on amd64 and ~half of that on x86, at the cost of lengthened build time.
sandbox Enable sandboxing functionality

pypy3

low-memory Build using PyPy with the engine configured towards low memory footprint. This makes it possible to build PyPy using ~3.5G of RAM on amd64 and ~half of that on x86, at the cost of lengthened build time.
sandbox Enable sandboxing functionality

python-stdnum

vies Enable VIES

pyudev

pygobject Install PyGobject bindings
qt5 Install PyQt5 bindings

pyyaml

libyaml enable support for C implementation using libyaml

pyzor

gdbm Enables the Gdbm back-end database engine for pyzord
gevent Use dev-python/gevent to enable asynchronous operation
mysql Enables the MySQL back-end database engine for pyzord through dev-python/mysql-python. Only works with python-2.x!
pyzord Enable the pyzord server daemon
redis Enables the redis back-end database engine for pyzord through dev-python/redis-py

rarfile

compressed Enables the module to support compressed v3 archives by calling the app-arch/unrar.

rdflib

redland enable support for Redland triplestore

restkit

cli Install the restcli command line interface/tool, based on dev-python/ipython

setuptools_scm

mercurial Enables mercurial backend

simplecv

shell Enable the iPython SimpleCV shell

simplespectral

faster Use sci-libs/scipy to speed up drawing
fastest Use dev-python/pyFFTW to speed up drawing to the max

sphinx

net enable internet capabilities

spyder

webengine Build bindings for the QtWebEngine module

sympy

imaging Add support for dev-python/pillow
ipython Add support for dev-python/ipython
mathml Add support for mathml
pyglet Use dev-python/pyglet for plots and print preview
symengine Add support for a dev-python/symengine backend
texmacs Add app-office/texmacs interface
theano Add support for dev-python/theano

tappy

yaml Pull dependencies needed to support YAML blocks associated with test results.

translate-toolkit

html Support conversion between po and html files
ical Support conversion between po and ical files
ini Support conversion between po and ini files
subtitles Support conversion between po and sub files
yaml Support YAML format

twisted

conch include Twisted SSHv2 implementation
http2 include http2 support
serial include serial port support

twisted-core

serial include serial port support

vatnumber

vies Enable VIES

ws4py

client Install client modules
server Install server modules

wxpython

examples Install interactive demo module browser and sample applets.

zeep

async Add async support
tornado Add tornado support

zsi

twisted add support for python-twisted (needs dev-python/twisted-core and dev-python/twisted-web)

dev-qt

designer

declarative Build the qdeclarativeview plugin
webkit Build the qwebview plugin

linguist-tools

qml Enable QML support in lupdate

qdoc

qml Enable QML/JS parsing support

qt-creator

android Build plugin for Android devices
autotools Enable autotools project manager plugin
baremetal Build plugin for bare metal devices
bazaar Add support for dev-vcs/bzr version control system
clangcodemodel Build clang-based code model and refactoring plugins
clangstaticanalyzer Build clang-based static analyzer plugin
clearcase Add support for IBM ClearCase version control system (requires manual installation of ClearCase client)
cmake Enable cmake project manager plugin
designer Build widget designer plugin
glsl Enable GLSL source code editor
ios Build plugin for Apple iOS devices
mercurial Add support for dev-vcs/mercurial version control system
modeling Enable graphical model editor
nim Enable Nim source code editor
perforce Add support for Perforce version control system (requires manual installation of Perforce client)
python Enable Python source code editor
qbs Enable QBS project manager plugin
qnx Build plugin for QNX devices
scxml Enable graphical SCXML editor
systemd Add support for retrieving application output from journald
valgrind Add support for memory debugging using dev-util/valgrind
webengine Use dev-qt/qtwebengine to view documentation
winrt Build plugin for WinRT devices

qt-docs

3d Install documentation for dev-qt/qt3d
bluetooth Install documentation for dev-qt/qtbluetooth
charts Install documentation for dev-qt/qtcharts
datavis Install documentation for dev-qt/qtdatavis3d
declarative Install documentation for dev-qt/qtdeclarative, dev-qt/qtquickcontrols, and dev-qt/qtquickcontrols2
graphicaleffects Install documentation for dev-qt/qtgraphicaleffects
html Install documentation in HTML format
location Install documentation for dev-qt/qtlocation
multimedia Install documentation for dev-qt/qtmultimedia
networkauth Install documentation for dev-qt/qtnetworkauth
qch Install documentation in QCH format
script Install documentation for dev-qt/qtscript
sensors Install documentation for dev-qt/qtsensors
speech Install documentation for dev-qt/qtspeech
virtualkeyboard Install documentation for dev-qt/qtvirtualkeyboard
webengine Install documentation for dev-qt/qtwebengine

qt3d

gles2 Use GLES 2.0 or later instead of full OpenGL
qml Build QML/QtQuick bindings

qtbluetooth

qml Build QML/QtQuick bindings and imports

qtcharts

qml Build QML/QtQuick bindings and imports

qtcore

systemd Enable native journald logging support

qtdatavis3d

gles2 Use GLES 2.0 or later instead of full OpenGL
qml Build QML/QtQuick bindings and imports

qtdeclarative

gles2 Use GLES 2.0 or later instead of full OpenGL
localstorage Build the LocalStorage import for QtQuick (requires QtSql)
widgets Enable QtWidgets support
xml Build the XmlListModel import for QtQuick (requires QtXmlPatterns)

qtdiag

network Report network information
widgets Report widget style information

qtgui

egl Enable EGL integration
eglfs Build the EGL Full Screen/Single Surface platform plugin
evdev Enable support for input devices via evdev
gles2 Use GLES 2.0 or later instead of full OpenGL
ibus Build the IBus input method plugin
libinput Enable support for input devices via dev-libs/libinput
tslib Enable support for touchscreen devices via x11-libs/tslib
tuio Build plugin to receive touch events over the TUIO protocol
xcb Build the XCB platform plugin and enable X11 integration

qtmultimedia

gles2 Use GLES 2.0 or later instead of full OpenGL
gstreamer Enable audio support via media-libs/gstreamer using SLOT 1.0
qml Build QML/QtQuick bindings and imports
widgets Build the QtMultimediaWidgets module

qtnetwork

bindist Disable EC support via dev-libs/openssl
connman Enable net-misc/connman-based bearer plugin
libproxy Use net-libs/libproxy for automatic HTTP/SOCKS proxy configuration
networkmanager Enable net-misc/networkmanager-based bearer plugin

qtopengl

gles2 Use GLES 2.0 or later instead of full OpenGL

qtpositioning

geoclue Use enhanced location information from app-misc/geoclue
qml Build QML bindings

qtprintsupport

gles2 Use GLES 2.0 or later instead of full OpenGL

qtquickcontrols

widgets Enable QtWidgets support

qtquickcontrols2

widgets Enable QtWidgets support

qtscript

scripttools Build the QtScriptTools module (requires QtWidgets)

qtsensors

qml Build QML bindings

qtvirtualkeyboard

handwriting Adds handwriting recognition integration support

qtwayland

libinput Enable support for input devices via dev-libs/libinput

qtwebchannel

qml Build QML/QtQuick bindings and imports

qtwebengine

designer Install the QWebEngineView plugin used to add widgets in dev-qt/designer forms that display web pages.
geolocation Enable physical position determination via dev-qt/qtpositioning
jumbo-build Combine source files to speed up build process.
pax_kernel Enable building under a PaX enabled kernel
system-ffmpeg Use the system-wide media-video/ffmpeg instead of bundled.
system-icu Use the system-wide dev-libs/icu instead of bundled.
widgets Enable QtWidgets support

qtwebkit

geolocation Enable physical position determination via dev-qt/qtpositioning
gles2 Use GLES 2.0 or later instead of full OpenGL
gstreamer Enable HTML5 audio/video support via media-libs/gstreamer using SLOT 1.0
hyphen Enable hyphenation support via dev-libs/hyphen
multimedia Enable HTML5 audio/video support via dev-qt/qtmultimedia
orientation Enable device orientation detection via dev-qt/qtsensors
printsupport Enable printing via dev-qt/qtprintsupport
qml Build QML/QtQuick bindings

qtwebsockets

qml Build QML bindings

qtwidgets

gles2 Use GLES 2.0 or later instead of full OpenGL

dev-ros

rosbag

lz4 Add support for lz4 compressed bags.

rosconsole

glog Use dev-cpp/glog as log backend.
log4cxx Use dev-libs/log4cxx as log backend.

dev-ruby

barby

cairo Add support for writing images (PNG, PS, EPS and, if supported, PDF and SVG) using dev-ruby/rcairo. Not available on JRuby.
png Add support for writing PNG images using dev-ruby/chunky_png.
prawn Add support for writing PDF documents using dev-ruby/prawn.
qrcode Add support for QRCode 2D codes using dev-ruby/rqrcode.
rmagick Add support for writing images (among others PNG, GIF and JPEG) using dev-ruby/rmagick. Not available on JRuby.

facter

dmi Use sys-apps/dmidecode to determine hardware system properties
pciutils Use sys-apps/pciutils to determine hardware system properties
virt Use app-emulation/virt-what for virtual machine detection

faraday_middleware

mashify Include FaradayMiddleware::Mashify
oauth Include FaradayMiddleware::OAuth
parsexml Include FaradayMiddleware::ParseXml
rashify Include FaradayMiddleware::Rashify

maruku

highlight Enable source code highlighting via dev-ruby/syntax

mysql2

mariadb Use mariadb bindings

net-ssh

ed25519 Use dev-ruby/ed25519 for Ed25519 support
sodium Use dev-libs/libsodium via dev-ruby/rbnacl for Ed25519 support

rails

asset-pipeline Also install the default components for the asset pipeline. These are not required but they are activated automatically in new Rails projects by default.

rrdtool-bindings

graph Enable support for graphing functions

rspec-core

highlight Enable source code highlighting via dev-ruby/coderay

ruby-sdl

image Enable media-libs/sdl-image support
mixer Enable media-libs/sdl-mixer support
sge Enable sdl-sge support

rubygems

server Install support for the rubygems server

dev-scheme

gauche

mbedtls Enable support for net-libs/mbedtls

gauche-gl

cg Enable NVidia Cg binding

gauche-gtk

glgd Enable GL graph draw

guile

debug-freelist Include garbage collector freelist debugging code
debug-malloc Include malloc debugging code
deprecated Enable deprecated features
discouraged (implied by deprecated) enable merely discouraged features
networking Include networking interfaces
regex Include regular expression interfaces

kawa

awt Assume AWT is available
echo2 Enable support for the Echo2 web toolkit with dev-java/echo2
frontend Build "kawa" front-end program using sys-libs/readline
jemacs Build JEmacs
krl Build BRL emulation and KRL
sax Assume SAX2 is available with dev-java/sax
servlets Build support for generating servlets with Java servletapi
swing Assume Swing is available
xqtests Support XQuery Test Suite

racket

futures Enable racket/future library for fine-grained hardware parallelism
places Enable racket/place library for share-nothing parallelism and message-passing communication. Compared to futures, places are heavyweight, but they have a simpler performance model.
threads Enable support for green threads

scm

arrays Support for arrays, uniform-arrays and uniform-vectors.
bignums Support for large precision integers.
cautious SCM will always check the number of arguments to interpreted closures.
dynamic-linking Be able to load compiled files while running.
engineering-notation Floats to display in engineering notation (exponents always multiples of 3) instead of scientific notation.
gsubr generalized c arguments: for arbitrary (more then 11) arguments to C functions.
inexact Support for floating point numbers.
ioext Commonly available I/O extensions: line I/O, file positioning, file delete and rename, and directory functions.
libscm Build and install libscm.a and related headers
macro C level support for hygienic and referentially transparent macros (syntax-rules macros).
regex String regular expression matching.
unix Support for: nice, acct, lstat, readlink, symlink, mknod and sync.

slib

gambit Support for gambit scheme implementation
scm Support for scm scheme implementation

dev-tcltk

expect-lite

debug pull in packages needed for runtime interactive debugger

tcl3d

ode Enable support for physics engine from dev-games/ode
osg Enable support for 3D toolkit from dev-games/openscenegraph

tktreectrl

shellicon shellicon extension

dev-tex

abntex

lyx Install with app-office/lyx layout

biblatex

biber Install the unicode compatible backend processor

circuit_macros

script Install cm2pdf to automatically create a correctly sized PDF from a circuit_macro m4 source

dot2texi

pgf Enable support for dev-tex/pgf (The TeX Portable Graphic Format)
pstricks Enable pstricks support

pythontex

highlighting Syntax highlighting using dev-python/pygments

dev-texlive

texlive-basic

luajittex Add support for LuaJitTeX: LuaTeX based on LuaJIT which is usually faster.

dev-util

android-ndk

legacy-toolchains Install legacy toolchains
target-32 Support for 32-bit targets
target-64 Support for 64-bit targets

anjuta

devhelp Enable devhelp integration
glade Build glade plugin for anjuta
packagekit Use packagekit to search for missing tools
terminal Enable terminal plugin based on x11-libs/vte

apitrace

cli Enable command line interface
egl Enable EGL support
system-snappy Link dynamic against app-arch/snappy

bazel

tools Install extra bazel tools to build from sources

bitcoin-tx

knots Build enhanced Bitcoin Knots version, rather than Bitcoin Core

buildbot

docker Add support for worker docker command steps
irc Add support for status delivery through an ircbot.
mail Add support for watching a maildir for commits.
manhole Add support for manhole (debug over ssh)

bustle

interactivetests Build interactive test programs
threaded Build with support for multithreaded execution.

catalyst

ccache Enables ccache support
system-bootloader Pulls in the depends needed to setup livecd bootloader from the host system rather than using a cdtar

cccc

apidoc Build software docs with doxygen/graphviz and metrics with cccc
mfc Add patch for MFC dialect options

clion

custom-jdk Install and use IntelliJ's custom JRE.

cmake

server Enable cmake-server support.
system-jsoncpp Use system copy of dev-libs/jsoncpp instead of bundled one.

coccigrep

vim Install the coccigrep vim plugin

codeblocks

contrib Build additional contrib components
fortran Build FortranProject plugin which enables to use Code::Blocks IDE for Fortran language

cppcheck

htmlreport install cppcheck-htmlreport

ctags

json Enable JSON output support
xml Enable XML parsing support
yaml Enable YAML parsing support

cutter

jupyter Add support for jupyter notebook
webengine Use dev-qt/qtwebengine for in-app jupyter browser

cwdiff

a2ps install app-text/a2ps for postscript output
mercurial install hg wdiff alias for dev-vcs/mercurial

devhelp

gedit Install plugin for app-editors/gedit

dialog

minimal Disable library, install command-line program only

diffoscope

R Use dev-lang/R
binutils Use sys-devel/binutils
colord Use x11-misc/colord
cpio Use app-arch/cpio
diff Use sys-apps/diffutils
docx Use app-text/docx2txt
dtc Use sys-apps/dtc
e2fsprogs Use sys-fs/e2fsprogs
file Use sys-apps/file
find Use sys-apps/findutils
gettext Use sys-devel/gettext
gpg Use app-crypt/gnupg
haskell Use dev-lang/ghc
hex Use app-editors/vim-core
iso Use virtual/cdrtools
llvm Use sys-devel/llvm
opendocument Use app-text/odt2txt
pascal Use dev-lang/fpc
rpm Use app-arch/rpm
squashfs Use sys-fs/squashfs-tools
ssh Use net-misc/openssh
tar Use app-arch/tar
tcpdump Use net-analyzer/tcpdump
xz Use app-arch/xz-utils
zip Use app-arch/unzip

edb-debugger

graphviz Add support for the Graphviz library
legacy-mem-write Probe if writes to /proc/PID/mem are broken.
pax_kernel Enable building under a PaX enabled kernel

edi

clang Provide integration with sys-devel/clang for autocompletion and inline errors

electron

gconf Use gnome-base/gconf
gtk3 Use GTK+3 instead of GTK+2
lto Build with link time optimization enabled
pic Disable optimized assembly code that is not PIC friendly
proprietary-codecs Enable proprietary codecs like H.264, MP3
system-ffmpeg Use system ffmpeg instead of the bundled one
tcmalloc Use bundled tcmalloc instead of system malloc

emilpro

system-binutils Use the gentoo binutils instead of building against an unpatched vanilla version

fatrace

powertop Add powetop integration

geany

gtk3 Use GTK+3 instead of GTK+2
vte Enable Terminal support (x11-libs/vte)

geany-plugins

autoclose Enable the autoclose plugin.
automark Enable the automark plugin
commander Enable the commander plugin which provides a command panel for rapid access to any action.
ctags Enable ctags plugin
debugger Enable the debugger plugin which interfaces with sys-devel/gdb
defineformat Enable the defineformat plugin.
enchant Enable spell checking using enchant
gpg Enable geanypg plugin which integrates GPG using app-crypt/gpgme
gtk3 Use GTK+3 instead of GTK+2
gtkspell Use gtkspell for dictionary support in GeanyVC
multiterm Enable the multiterm plugin
overview Enable overview plugin
pretty-printer Enable pretty-printer plugin
scope Enable the scope plugin which is a graphical GDB front-end
soup Enable updatechecker and geniuspaste plugins which require net-libs/libsoup

global

vim Integrate the GNU GLOBAL source code tag system with Vim

gnome-builder

clang Provide integration with sys-devel/clang for best possible C/C++ autocompletion, semantic highlighting, symbol resolving, and diagnostics support
devhelp Provide API docs browsing and integration via dev-util/devhelp
git Provide support for the Git version control system via dev-libs/libgit2-glib (such as setup of Git for New Project, direct cloning for Open Project and changed lines indicators in the editor gutter)
sysprof Provide an integrated profiler via dev-util/sysprof
vala Provide an autoindenter, autocompletion, diagnostics, and symbol resolver for Vala
webkit Enable net-libs/webkit-gtk using plugins support and the HTML/Markdown previewer plugin

google-perftools

debug Build a set of libraries with debug support (so-called debugalloc). These are available by default but are not needed unless you're actually developing using tcmalloc.
largepages Use (experimental) larger pages for tcmalloc, this increases memory usage, but should speed up the allocation/free operations.
minimal Only build the tcmalloc_minimal library, ignoring the heap checker and the profilers.
optimisememory To build libtcmalloc with smaller internal caches.

gtk-doc

highlight Enable source code highlighting
vim Enable source code highlighting through app-editors/vim

heaptrack

zstd Enable support for ZSTD compression using app-arch/zstd

idea-community

custom-jdk Install and use IntelliJ's custom JRE.

idea-ultimate

custom-jdk Install and use IntelliJ's custom JRE.

intel-ocl-sdk

android Install android related files
system-boost Use system boost (dev-libs/boost) instead of bundled one
system-clang Use system clang (sys-devel/clang) instead of bundled one
system-tbb Use system Thread Building Blocks (dev-cpp/tbb) instead of bundled one
tools Install Intel Offline Compiler

kdevelop

gdbui Enable GUI for attaching GDB to a running process
hex Enable hex editor plugin via app-editors/okteta
qmake Enable support for QMake build system
reviewboard Enable reviewboard support
webkit Enable deprecated dev-qt/qtwebkit instead of dev-qt/qtwebengine for integrated documentation

ltrace

unwind Use sys-libs/libunwind for frame unwinding support

lttng-tools

ust Support LTTng-UST (Userspace Tracing)

massif-visualizer

callgraph Enable detailed snapshot analysis using media-gfx/kgraphviewer

mdds

valgrind Add support for memory debugging using dev-util/valgrind

mingw64-runtime

idl Install idl files.
libraries Build extra libraries: mangle, pseh, winpthreads.
tools Build extra tools: gendef, genidl.

molecule

plugins Add plugins provided by dev-util/molecule-plugins

nemiver

memoryview Enable the optional hexadecimal memory inspection with app-editors/ghex

nvidia-cuda-sdk

cuda Build CUDA binaries
opencl Build OpenCL binaries

nvidia-cuda-toolkit

debugger Installs the CUDA debugger
eclipse Install plugins for eclipse
profiler Installs the NVIDIA CUDA visual profiler

ostree

grub Enable grub configuration generator
soup Use libsoup for networking

perf

demangle Enable C++ symbol name demangling, using libbfd from sys-devel/binutils. When this flag is enabled, the package will have to be rebuilt after every version bump of binutils.
doc Build documentation and man pages. With this USE flag disabled, the --help parameter for perf and its sub-tools will not be available. This is optional because it depends on a few documentation handling tools that are not always welcome on user systems.
numa Enable NUMA support
perl Add support for Perl as a scripting language for perf tools.
unwind Use sys-libs/libunwind for frame unwinding support.

pkgconf

pkg-config Install as a replacement for dev-util/pkgconfig

pkgconfig

internal-glib Use internal copy of dev-libs/glib

pkgconfig-openbsd

pkg-config Install as a replacement for dev-util/pkgconfig

radare2

system-capstone Use dev-libs/capstone instead of bundled copy.

scanmem

gui Enable the GameConqueror GUI

schroot

btrfs Enable support for chroots using btrfs snapshots.
dchroot Enables the building of a wrapper named "dchroot", replacing sys-apps/dchroot.
lvm Enable support for chroots using LVM snapshots.

squashdelta

lz4 Enable support for LZ4 compression using app-arch/lz4

squashmerge

lz4 Enable support for LZ4 compression using app-arch/lz4

strace

aio Enable dev-libs/libaio support for tracing Asynchronous I/O operations
elfutils Enable stack backtraces (-k flag) via dev-libs/elfutils
unwind Enable stack backtraces (-k flag) via sys-libs/libunwind

suse-build

symlink Provide compatibility symlinks with original openSUSE package (might clash with other packages)

sysdig

modules Build kernel modules needed for tracing local events. Disable this only if you intend to use sysdig purely to work with dumpfiles.

sysprof

systemd Build the sysprofd daemon service, required to run the UI without root permissions. Relies on sys-apps/systemd running as the init system.

systemtap

libvirt Support probing of libvirt domains.

trace-cmd

udis86 Enable support for dev-libs/udis86 disassembler library

vulkan-tools

cube Build the cube/cubepp demos
vulkaninfo Build the vulkaninfo utility

dev-vcs

bzr

sftp Enable sftp support

cssc

valgrind Enable usage of dev-util/valgrind in tests

cvs

server Enable server support

cvs2svn

bazaar Support for dev-vcs/bzr

cvsync

gcrypt Use dev-libs/libgcrypt for hash functions.
mhash Use app-crypt/mhash for hash functions.
openssl Use dev-libs/openssl for hash functions.

darcs

diff Use 'lcs' for diff building.
http Use the pure Haskell HTTP package for HTTP support.
network-uri Get Network.URI from the network-uri package.
terminfo Use the terminfo package for enhanced console support.
threaded Use threading and SMP support.

fossil

fusefs Enable the Fuse Filesystem
json Enable the JSON API of Fossil's wiki
legacy-mv-rm Enable legacy behavior for mv/rm (skip checkout files).
miniz Use the bundled miniz for compression instead of zlib. Incompatible with ssl.
system-sqlite Use the system SQLite instead of the bundled one
tcl-private-stubs Enable Tcl integration via private stubs mechanism
tcl-stubs Enable Tcl integration via stubs library mechanism
th1-docs Enable TH1 for embedded documentation pages
th1-hooks Enable TH1 hooks for commands and web pages

git

blksha1 Use the new optimized SHA1 implementation
cgi Install gitweb too
curl Support fetching and pushing (requires webdav too) over http:// and https:// protocols
gpg Pull in gnupg for signing -- without gnupg, attempts at signing will fail at runtime!
highlight GitWeb support for app-text/highlight
mediawiki Support pulling and pushing from MediaWiki
mediawiki-experimental Add experimental patches for improved MediaWiki support
pcre-jit Enable JIT for pcre
ppcsha1 Make use of a bundled routine that is optimized for the PPC arch
subversion Include git-svn for dev-vcs/subversion support
tk Include the 'gitk' and 'git gui' tools
webdav Adds support for push'ing to HTTP/HTTPS repositories via DAV

git-annex

assistant Enable git-annex assistant and watch command
benchmark Enable benchmarking
concurrentoutput Use concurrent-output library (experimental)
magicmime Use libmagic to determine file MIME types
network-uri Get Network.URI from the network-uri package.
pairing Enable pairing of git annex repositories
s3 Enable Amazon S3 remote
torrentparser Use haskell torrent library to parse torrent files
webapp Enable git-annex webapp
webdav Enable webdav remote

gitg

glade Install a glade catalog file
python Install Python bindings for those plugins requiring it.

gitolite

contrib Install user-contributed files
tools Install tools to e.g. convert a Gitosis config to gitolite or one to check if your setup is gitolite >= 3.x compatible

gitolite-gentoo

contrib Install user-contributed files
tools Install tools to e.g. convert a Gitosis config to gitolite or one to check if your setup is gitolite >= 3.x compatible

kdesvn

man Build and install man pages

mercurial

bugzilla Support bugzilla integration.
gpg Support signing with GnuPG.
tk Install dev-lang/tk for hgk script.

rabbitvcs

caja Enable extension for mate-base/caja
cli Eanble console based frontend
diff Use for diff command dev-util/meld
gedit Enable plugin for app-editors/gedit
nautilus Enable extension for gnome-base/nautilus
thunar Enable extension for xfce-base/thunar

subversion

ctypes-python Build and install Ctypes Python bindings
dso Enable runtime module search
extras Install extra scripts (examples, tools, hooks)
http Enable http support using net-libs/serf
kwallet Enable encrypted storage of passwords with kde-frameworks/kwallet

games-action

beathazardultra

bundled-libs Use the upstream provided bundled libraries.

chromium-bsu

mixer Enables media-libs/sdl-mixer sound backend instead of media-libs/openal one.

d1x-rebirth

demo Use the demo data instead of the full game
l10n_de Provides German translations for the game's briefings, robot descriptions, and outro of the original campaign
music Support for ingame music
opl3-musicpack Include alternate version of the game's music, recorded with the Yamaha YMF262 OPL3 soundchip
sc55-musicpack Include alternate version of the game's music, recorded with the Roland Sound Canvas SC-55 MIDI module

dxx-rebirth

data Install data files
descent1 Install Descent 1 resources and executable
descent2 Install Descent 2 resources and executable
l10n_de Provides German translations for the game's briefings, robot descriptions, and outro of the original campaign
music Enable music support
opl3-musicpack Include alternate version of the game's music, recorded with the Yamaha YMF262 OPL3 soundchip
sc55-musicpack Include alternate version of the game's music, recorded with the Roland Sound Canvas SC-55 MIDI module
textures Include high resolution (640x480) backgrounds, briefing images and fonts (Descent 1)

hotline-miami

bundled-libs Use bundled libraries.
launcher Install qt launcher

minetest

jsoncpp Enable using a system-wide JSONCPP
leveldb Enable LevelDB backend
postgres Optionally use PostgreSQL as map backend
redis Enable redis backend via dev-libs/hiredis
server Build minetest server
spatial Enable SpatialIndex AreaStore backend

solar2

bundled-libs Use the upstream provided bundled libraries.

supermariowar

server Compile and install Super Mario War server files

supertuxkart

fribidi Support for right-to-left languages
recorder Enable recording with media-libs/libopenglrecorder
wiimote Support for wiimote input devices

swordandsworcery

bundled-libs Use the upstream provided bundled libraries.

trine

launcher Install GTK+ launcher

trine-enchanted-edition

launcher Install GTK+ launcher

trine2

launcher Install GTK+ launcher

games-arcade

bomns

editor enables building the level editor

burgerspace

network Enable client-server support

commandergenius

tremor Use media-libs/tremor as ogg decoder instead of media-libs/libvorbis

jumpnbump

music Enable playing of background music

lbreakout2

themes Install additional themes

moleinvasion

music Download and install the music files

oshu

osu-skin Include more complete osu-skin (other is minimal)

performous

midi Enable MIDI I/O support
songs Install a few demo songs
tools Enable building of song extraction utilities for SingStar and Guitar Hero
webcam Enable Webcam support

savagewheels

fmod Enable the fmod music and sound effects library

slimevolley

net Enable network support

tuxanci

physfs Use dev-games/physfs instead of dev-libs/libzip to load compressed data
sound Enable sound

games-board

cockatrice

client Build with client
oracle Build with oracle
server Compile server support

crafty

no-opts Don't try to enable crazy CFLAG options

freedoko

backgrounds Install additional background images
gnomecards Install the gnome-games card set
kdecards Install the KDE card set
net Enable network game support
openclipartcards Install the openclipartcards card set
pysolcards Install the PySol card set
xskatcards Install the XSkat card set

grhino

gtp Install the GTP (Go/Game Text Protocol) frontend

pasang-emas

extras Install some extra themes

pioneers

help Enable gnome ingame help via scrollkeeper

pysolfc

extra-cardsets Install extra cardsets
sound Enable sound support using dev-python/pygame

spider

athena Enable athena widgets

stockfish

armv7 Build for armv7; enables PIE
general-32 Generic unoptimized 32-bits build
general-64 Generic unoptimized 64-bits build
optimize Enable upstream -O3 optimizations (default enabled)

tablebase-syzygy

6-pieces Install tablebases for 6 pieces (huge!)

xboard

default-font Install the default font that xboard uses
zippy Enable experimental zippy client

games-emulation

dolphin

discord-presence Enables Discord Rich Presence, show the current game on Discord
egl Enable EGL support
evdev Enable evdev input support
log Increase logging output
lto Add support for link-time optimizations.

dosbox

glide Enable unofficial Glide emulation via media-libs/openglide

fceux

logo Enable the ability to add a logo screen when creating AVIs

generator

sdlaudio Enable SDL Audio

hatari

sdl2 Use libsdl2 instead of libsdl

higan

icarus Build icarus library manager
udev Enable udev based input

m64py

7z Ensure support for .7z archives.
rar Ensure support for .rar archives.

mednafen

debugger Build with internal debugger
pax_kernel Triggers a paxmarking of the binary

mupen64plus

audio-sdl Enable SDL audio plugin.
input-sdl Enable SDL input plugin.
rsp-hle Enable HLE RSP plugin.
ui-console Enable default console UI.
ui-m64py Enable PyQt5 UI using games-emulation/m64py.
video-glide64mk2 Enable Glide64mk2 video plugin.
video-rice Enable Rice video plugin.

mupen64plus-core

debugger Build the debugger
gles2 Use GLES2 instead of OpenGL
new-dynarec Enable new experimental dynamic recompiler implementation (only for x86 and arm)
osd Overlay emulator messages using on-screen-display

mupen64plus-video-glide64mk2

gles2 Use GLES2 instead of OpenGL
hires Support hi-resolution textures (requires dev-libs/boost)

mupen64plus-video-rice

gles2 Use GLES2 instead of OpenGL

nestopia

gui Enable GUI

pcsxr

cdio Use libcdio for CD support
sdl Use SDL sound backend (other parts of SDL are used unconditionally)

ppsspp

headless Build headless version of the PPSSPP
system-ffmpeg Use the system-wide media-video/ffmpeg instead of bundled

snes9x

netplay Enable playing ROMs over the network (not recommended)

vbam

link Enable GBA linking functionality

zsnes

debug Enable the builtin debugger
pax_kernel Triggers a paxmarking of the binary

games-engines

exult

sdl2 Use libsdl2 instead of libsdl

frobtads

tads2compiler Build TADS2 compiler
tads3compiler Build TADS3 compiler

odamex

master Build master server target (advertises odamex server list)
odalaunch Build the wxwidgets based launcher.
portmidi Enable portmidi support.
server Build server target.

openmw

devtools Install development tools like bsatool, esmtool and opencs.

renpy

development Install IDE for game developers and an empty game template

scummvm

fluidsynth compile with support for fluidsynth
mpeg2 enable mpeg2 codec for cutscenes
unsupported enable unsupported and/or broken game engines (you're on your own)

solarus

doc Install doxygen developer documentation.

stratagus

fluidsynth compile with support for fluidsynth

games-fps

alienarena

vidmode Link against x11-libs/libXxf86vm. Required for full-screen support.

darkplaces

cdsound Enables using CD audio in the engine
demo Uses the demo data from quake1 (quake1-demodata)
lights Install and setup the updated light maps
textures Install and setup the updated textures

doom-data

doomsday Add wrapper to run it within doomsday

doom3

dedicated install only as a dedicated game server
roe Adds support for the Resurrection of Evil expansion

doomsday

demo Install launcher dor doom1.wad from games-fps/doom-data
doom Install launcher for jdoom game
fluidsynth Build the FluidSynth sound driver
fmod Enable support for fmod music and sound effects lib
freedoom Install launcher for doom1.wad from games-fps/freedoom
heretic Install launcher for jheretic game
hexen Install launcher for jhexen game
tools Build additional tools such as doomsday-shell, md2tool and texc

duke3d-data

gog Extract the data from the GOG.com installer.

eduke32

demo Install the Duke Nukem 3D demo files, provided by games-fps/duke3d-demodata.
fluidsynth Install media-libs/sdl2-mixer with fluidsynth support.
hrp Install the Duke Nukem 3D High Resolution Pack.
offensive Install the Duke Nukem 3D XXX Pack.
opl Install the Duke Nukem 3D OPL music files.
psx Install the Duke Nukem 3D PSX high resolution voice files.
sc-55 Install the Duke Nukem 3D Roland SC-55 music files.
sdk Install the SDK files.
server Enable support for multiplayer.
tools Install the support tools for mapster32.
voxels Install the Duke Nukem 3D Voxels Pack.
vpx Enable support for media-libs/libvpx.
xmp Enable support for media-libs/exempi.

nexuiz

maps Install the community map pack

quake2-icculus

demo Install the demo files (quake2-demodata) and configure for use
qmax Build the pretty version (quake max)
rogue Build support for the 'Ground Zero' Mission Pack (rogue)
xatrix Build support for the 'The Reckoning' Mission Pack (xatrix)

quake3

mumble Adds player-location (positional audio) support to VoIP
teamarena Adds support for Team Arena expansion pack
voice Adds VoIP support

quake3-bin

teamarena Adds support for Team Arena expansion pack

quake3-demo

dedicated install only as a dedicated game serer

quakeforge

wildmidi enable libWildMidi support
xdg enable XDG support

qudos

demo Install the demo files (quake2-demodata) and configure for use
mods Build support for the quake2 mission packs
qmax Build the pretty version (quake max)
textures Install the enhanced textures (quake2-textures)

redeclipse

dedicated Install only as a dedicated game server

rott

demo Install the shareware version

sauerbraten

server Compile server support

turtlearena

mumble Adds player-location (positional audio) support to VoIP
server Build server target
voice Adds VoIP support

unreal-tournament-goty

S3TC Add the extra fancy textures to UT ... only works on certain cards (nvidia/ati/s3)

urbanterror

altgamma Alternative way for gamma setting with modesetting driver
client Build binary for client (includes code for non-dedicated server)
mumble Use Mumble for ingame VoIP (experimental)
server Build binary for dedicated server
skeetshootmod Build support for skeetshoot mod for specific maps
voip Use ioq3 ingame VoIP (experimental)

worldofpadman

maps Install extra maps (PadPack)

xonotic

ode Enable support for physics engine from dev-games/ode

yamagi-quake2

client Build client
ctf Build support for the 'Capture The Flag' addon
rogue Build support for the 'Ground Zero' Mission Pack
softrender Build software renderer
xatrix Build support for the 'The Reckoning' Mission Pack

games-misc

katawa-shoujo

system-renpy Use games-engines/renpy instead of the bundled one (experimental)

little-inferno

bundled-libs Use bundled libraries.

ponysay

fish-completion Enable fish completion support
non-free Install non-free ponies (i.e. from the MLP franchise)

xcowsay

fortune Installs the fortune-mod xcow binary

games-mud

tf

atcp enable ATCP support.
gmcp enable GMCP support.
option102 enable telnet option 102 support.

games-puzzle

cuyo

music Enable playing of background music

nightsky

bundled-libs Use the upstream provided bundled libraries.

numptyphysics

user-levels Install some fun user-created levels

pingus

music Enable playing of background music

sgt-puzzles

gtk3 Use x11-libs/gtk+:3 instead of x11-libs/gtk+:2

tiny-and-big

bundled-libs Use the upstream provided bundled libraries.

xlogical

alt_gfx Use alternate graphics which are closer to the original Amiga version

games-roguelike

FTL

bundled-libs Use bundled libraries.

angband

sound Enable and install sounds

nethack

experimental Enable experimental features (showscore and status_hilite)

stone-soup

ncurses Enable for console (uses ncurses) based build. (can be enabled on top of tiles)
tiles Enable for graphical (tiled) build. (can be enabled on top of ncurses)

tomenet

server Compile server support

games-rpg

arx-fatalis-data

gog Extract the data from the GOG.com installer.

arx-libertatis

c++0x Build ROOT using the C++11 standard.
crash-reporter Build a dev-qt/qtgui-based tool that allows to submit crash information to the upstream backtracker.
debug Enable asserts and debug logging.
static Link libraries statically, currently only media-libs/glew
tools Build tools that can extract the game's data and save files.
unity-build Build everything in one big source file, allowing for faster build times and better optimizations at the cost of higher memory usage.

daimonin-client

music Install extra music

drascula

sound Install optional audio files

dreamweb

doc High-resolution scans of the written material in the original UK game box

dungeon-defenders

bundled-libs Use the upstream provided bundled libraries.

eternal-lands-data

bloodsuckermaps Will install Bloodsucker's Maps in place of the official map files
music Enables in-game music
sound Enables in-game sound effects

kqlives

cheats Enable cheating mode

manaplus

mumble Enable support for voice chat
pugixml Use dev-libs/pugixml for XML parsing isntead of dev-libs/libxml2
sdl2 Use libsdl2 instead of libsdl

sumwars

tools Builds editor tools

to-the-moon

bundled-libs Use bundled libraries

games-simulation

corsix-th

midi Adds support for background MIDI music via SDL_mixer

flightgear

dbus Enable screensaver DBus interaction
gdal Enable alternative terrain engine based on pagedLOD using sci-libs/gdal
qt5 Build Qt5 launcher application
udev Enable event-based Input devices through virtual/udev
utils Build various utilities (fgpanel, fgviewer among others)

openrct2

multiplayer Enable multiplayer functionality
twitch Enable Twitch support

openttd

aplaymidi Enables midi music in game, using aplaymidi as an external player
dedicated Build only the openttd server, and not the client.
lzo Enables LZO compression for savegames. This is only needed to load extremely old savegames. (versions before 0.2)
openmedia Enables the free open media sets: OpenGFX, OpenSFX, OpenMSX, removing the requirement for proprietary TTD assets to play OpenTTD.

singularity

music Install music files

games-sports

speed-dreams

xrandr Enable support for the X xrandr extension

xmoto

double-precision more precise calculations at the expense of speed
editor Depend on inkscape, scripts to convert svg to level (svg2lvl)

games-strategy

0ad

editor Include Atlas scenario editor projects
lobby Enable the use of net-libs/gloox and the multiplayer lobby
nvtt Support for some uncompressed data formats via media-gfx/nvidia-texture-tools (might be needed for some mods)

colobot

devbuild TODO
tools Build tools

colobot-data

music Enable music support
music_flac_convert Fetch flac music and convert it to ogg
music_ogg Fetch ogg music

defcon-demo

system-libs Use system libraries instead of the ones included in the upstream distribution.

freeciv

aimodules Support for dynamically loadable AI modules (server-side)
auth Add authentication capability via mysql, postgres or sqlite3
mapimg Additional mag image toolkit via media-gfx/imagemagick
modpack Build the freeciv-modpack-program to download/install mods
server Enable server support. Disabling this will also make it impossible to start local games.
sound Add support for sound provided by media-libs/sdl-mixer
system-lua Use dev-lang/lua instead of the bundled liblua

freesynd

devtools Build development tools

hedgewars

server Enable local server

heroes3

maps Installs optional map data
music Installs optional music data
sounds Installs optional sound data

ja2-stracciatella

editor Adds necessary file to run the editor
ru-gold Support for russian gold ja2 version

liquidwar6

doc Convert the info pages to html
gles2 Enable OpenGL ES 2.0 support
gtk Used to display error/critical messages
maps Install extra maps
ogg Enable mod-ogg via media-libs/sdl-mixer (currently the only sound provider)
readline Enable interactive script shell for hacking

megaglest

editor Build map editor
fribidi Enable FriBIDi support
model-viewer Build model viewer
streflop Use the library streflop. Out of synchs may occur if not enabled.
tools Build model import/export tools
unicode Use unicode strings for wxwidgets
wxuniversal Use the wxUniversal port which implements the various GUI controls by drawing them itself

naev

mixer Enables media-libs/sdl-mixer sound backend in addition to media-libs/openal one.

ufoai

client Build the main game client
editor Build the map editor and compiler
server Build the dedicated server

uqm

music download and install music files (large)
remix download and install music remix files (large)
voice download and install voice files (large)

wesnoth

fribidi Support for right-to-left languages
server Enable compilation of server

games-util

gslist

web Enable the web interface

pyfa

graph Enable support for graphs

wit

fuse Enable image mount support via fuse

gnome-base

gconf

ldap Build backend which enables default mail accounts, addressbooks and calendars for Evolution to be configured using each user's LDAP entry."

gdm

fprint Enables experimental fingerprint authentication using sys-auth/fprintd
plymouth Enable support for smooth transition from sys-boot/plymouth

gnome

classic Install gnome-extra/gnome-shell-extensions for the Gnome Shell Classic mode
extras Install additional GNOME applications

gnome-common

autoconf-archive Pull in sys-devel/autoconf-archive for ax_*.m4 files instead of installing them from the gnome-common tarball

gnome-control-center

colord Support color management using x11-misc/colord
gnome-online-accounts Enable configuration panel for net-libs/gnome-online-accounts accounts
ibus Enable support for enhanced input methods through app-i18n/ibus

gnome-desktop

license-docs Install help files documenting GNOME's licenses

gnome-extra-apps

games Install Gnome Games
share Install the gnome-extra/gnome-user-share personal file sharing tool
shotwell Install the media-gfx/shotwell photo manager
tracker Install the app-misc/tracker indexer and the GNOME packages that require it

gnome-keyring

ssh-agent Use GNOME Keyring to unlock SSH keys. Recommended unless you are using ECDSA or Ed25519 keys.

gnome-light

gnome-shell Install gnome-base/gnome-shell and x11-wm/mutter for the standard GNOME 3 desktop mode

gnome-settings-daemon

colord Support color management using x11-misc/colord
elogind Rely on sys-auth/elogind as runtime logind provider
openrc-force Skip systemd dependency (#480336), enabling this flag will become your setup to be fully unsupported by upstream and downstream Gnome team. Do not try to enable it unless completely needed
systemd Rely on sys-apps/systemd as runtime logind provider

gnome-shell

browser-extension Ensure the presence of extensions.gnome.org native connector gnome-extra/chrome-gnome-shell
elogind Use sys-auth/elogind for session tracking and suspend support.
ibus Enable support for enhanced input methods through app-i18n/ibus
openrc-force Skip systemd dependency (#480336), enabling this flag will become your setup to be fully unsupported by upstream and downstream Gnome team. Do not try to enable it unless completely needed
telepathy Ensure presence of telepathy chat integration

gvfs

afp Enables support for accessing AFP (Apple Filing Protocol) network shares
archive Enables support for accessing files in archives transparently via app-arch/libarchive
bluray Enable playback of Blu-ray filesystems using media-libs/libbluray
elogind Use sys-auth/elogind for session tracking.
fuse Enables fuse mount points in $HOME/.gvfs for legacy application access
gnome-online-accounts Enable configuration panel for net-libs/gnome-online-accounts accounts
google Enables support for accessing Google accounts via dev-libs/libgdata
http Enable the HTTP/DAV backend using net-libs/libsoup
nfs Enable NFS client support via net-fs/libnfs.
udev Enable udev base replacement code for cdda feature

libglade

tools Install libglade-convert Python script.

libgnomecanvas

glade Enable glade support

librsvg

tools Build svg viewer tool

nautilus

packagekit Use packagekit to search for programs to open unknown file types
previewer Use gnome-extra/sushi to preview files from the file mananger
sendto Enable the nautilus-sendto extension to send files to various locations/devices
tracker Add support for app-misc/tracker search

orbit

pic Force libname-server-2 to be built as PIC; needed on hardened systems

gnome-extra

cinnamon-control-center

colord Support color management using x11-misc/colord

cinnamon-settings-daemon

colord Support color management using x11-misc/colord

evolution-data-server

api-doc-extras Build documentation for private APIs
berkdb sys-libs/db support needed to migrate old (pre-3.12 evolution versions) addressbook data
gnome-online-accounts Enable net-libs/gnome-online-accounts based Google authentication support
google Enable internal Google authentication support. If gnome-online-accounts is enabled and used, this is not necessary, but both can be supported at the same time with different setup at runtime
weather Enable optional weather calendar support

gnome-color-manager

packagekit Enable support for the distro-neutral package manager GUI app-admin/packagekit

gnome-commander

chm Enable metadata support for Microsoft Compiled HTML Help files
gsf Add metadata support for OLE, OLE2 and ODF
pdf Add metadata support for PDF
python Add support for python plugins
samba Add support for SAMBA (Windows File and Printer sharing)
taglib Add metadata support for ID3, Vorbis, FLAC and APE
unique Enable single instance support using dev-libs/libunique

gnome-dvb-daemon

totem Build a plugin for media-video/totem

gnome-system-monitor

systemd Display sys-apps/systemd metadata, e.g. unit names, for running processes

libgda

canvas Enable support for x11-libs/goocanvas
http Enable embedded net-libs/libsoup based server
json Enable support for JSON format
mdb Enable support for Microsoft Access database using app-office/mdbtools
reports Install tools for generating graphical reports
sourceview Enable support for x11-libs/gtksourceview

libgsf

gtk Enable use of gdk in thumbnailer

nemo

packagekit Use packagekit to search for programs to open unknown file types
tracker Add support for app-misc/tracker search

nm-applet

gcr Enable advanced certificate chooser, requires app-crypt/gcr
modemmanager Enable support for mobile broadband devices using net-misc/modemmanager
teamd Enable teamd configuration editor

sushi

office Support viewing file formats such as generated by app-office/libreoffice

synapse

indicator Build support for application indicators using dev-libs/libappindicator
plugins Build support for plugins using net-libs/rest

gnustep-apps

gemas

projectcenter Build and install plugin for gnustep-apps/projectcenter

gworkspace

gwmetadata Enable the metadata indexing and searching system

gnustep-base

gnustep-back-art

xim Enable X11 XiM input method

gnustep-back-cairo

xim Enable X11 XiM input method

gnustep-back-xlib

xim Enable X11 XiM input method

gnustep-gui

speech Audio support using app-accessibility/flite

gnustep-make

libobjc2 Enables use of the GNUstep Objective-C runtime (gnustep-base/libobjc2) with non-fragile ABI and sys-devel/clang compiler
native-exceptions Enables use of the native Objective-C exception support (@try/@catch/@finally) built-in objective-c exceptions with compilers that support it

libobjc2

boehm-gc Enable Hans Boehm's garbage collector (dev-libs/boehm-gc). Not recommended by upstream

kde-apps

akonadi

designer Install plugin for dev-qt/designer
tools Install tools for developers and testing

analitza

eigen Enable dev-cpp/eigen mathematical templates support

ark

zip Enable ZIP archive support via dev-libs/libzip

artikulate

qtmedia Enable playback via Qt5Multimedia

cantor

R Enable dev-lang/R backend support
analitza Enable kde-apps/analitza backend support
julia Enable dev-lang/julia backend support
qalculate Enable sci-libs/libqalculate backend support

dolphin

thumbnail Enables thumbnail generation

dolphin-plugins

bazaar Enable support for the bazaar VCS
dropbox Enable support for the dropbox fileviewer plugin
git Enable support for the git VCS
mercurial Enable support for the mercurial VCS

gwenview

activities Enable kactivities support
fits Enable support for NASA's sci-libs/cfitsio library
kipi Enable support for the KDE Image Plugin Interface
mpris Enable support for MPRIS2 interface, requiring dev-qt/qtdbus as dependency.

k3b

emovix Enable burning support for eMoviX images

kalzium

editor Enable the embedded molecule editor/viewer
solver Enable the equation solver

kanagram

speech Enable text-to-speech support

kate

addons Build and install additional plugins

kde-apps-meta

pim Pull in KDE PIM suite
sdk Pull in developer-specific meta-packages

kdeadmin-meta

cron Installs KDE application for virtual/cron configuration

kdeedu-meta

webengine Enable kde-apps/kalzium and kde-apps/parley, requiring dev-qt/qtwebengine

kdegraphics-mobipocket

thumbnail Enables thumbnail generation

kdemultimedia-meta

cdrom Include packages for optical discs

kdenetwork-meta

telepathy Enable support for Plasma Telepathy (instant messaging) integration via kde-apps/plasma-telepathy-meta

kdenlive

freesound Enable freesound.org credentials support via dev-qt/qtwebkit to download files
gles2 Use GLES 2.0 or later instead of full OpenGL
jogshuttle Enable support for Jog-Shuttle devices
share Enable support for a share menu using kde-frameworks/purpose

kdepim-addons

importwizard Enable additional import plugins for kde-apps/akonadi-import-wizard

kdepim-runtime

speech Enable text-to-speech support

kdeutils-meta

floppy Install kde-apps/kfloppy to format and create DOS or ext2fs filesystems in a floppy.

keditbookmarks

man Build and install man pages

kget

bittorrent Enable bittorrent transfer plugin through net-libs/libktorrent
gpg Enable signature verification by GpgME++ via app-crypt/gpgme
mms Enable MMS (Microsoft Media Server) plugin through media-libs/libmms

kig

geogebra Support files created by sci-mathematics/geogebra
scripting Support Python scripting

kio-extras

activities Enable activities kioslave and fileitem plugin
htmlthumbs Enable HTML thumbnail previews via dev-qt/qtwebengine
man Enable manpages kioslave
phonon Enable file audio preview plugin using media-libs/phonon
sftp Enable SFTP protocol support using net-libs/libssh
taglib Enable audio thumbnails via media-libs/taglib

kmag

keyboardfocus Enable keyboard focus tracking

knights

speech Enable text-to-speech support

konqueror

activities Enable kactivities support
speech Build text-to-speech plugin
webengine Enable dev-qt/qtwebengine as web browser engine (fallback is kde-misc/kwebkitpart)

kopete

addbookmarks Automatically add incoming urls to bookmarks.
autoreplace Automatically replace selected text
contactnotes Enables writing personal notes for contacts.
gadu Enable the Gadu protocol handler.
groupwise Enable the Groupwise protocol handler.
highlight Allows you to specify highlights on specific events.
history Enables saving chat history.
latex Embed latex formatted text into messages.
meanwhile Enable the Sametime protocol handler.
nowlistening Shows song you currently listen to in your status/etc. Bindings for many players.
otr Allows crypting your chat (drugs and talking nonsense are considered as good alternatives ;]).
pipes Send messages to external pipe.
privacy Filter for incoming messages
statistics Everybody loves statistic graphs, especially cake ones. ;]
testbed Enable the testbed protocol.
texteffect Various fancy text effects for your messages (don't ever consider writing us with this enabled ;]).
translator Translate incoming and outgoing messages.
urlpicpreview Enables in conversation pictures preview.
webpresence Show your status and some more information on web.
winpopup Enable pop-up messages sending on windows. (same as good old "net send" messages ;])
zeroconf Enable Link-Local Messaging via the bonjour protocol.

kpimtextedit

designer Build plugins for dev-qt/designer
speech Enable text-to-speech support

ktp-accounts-kcm

experimental Enables disabled telepathy services (currently only steam)

ktp-common-internals

otr Enable support for encrypted conversations using Off-The-Records messaging
sso Enable support for Single sign-on through KAccounts

ktp-text-ui

speech Enable incoming messages to be read out using text-to-speech

kwave

qtmedia Enable playback via Qt5Multimedia

libkdepim

designer Build plugins for dev-qt/designer

libksane

kwallet Enable encrypted storage of passwords with kde-frameworks/kwallet

mailcommon

designer Build plugins for dev-qt/designer

marble

aprs Enable support for APRS data sources
designer Install plugin for dev-qt/designer
phonon Enable sound support via media-libs/phonon
shapefile Enable support for ESRI shapefiles

okular

chm Enable support for Microsoft Compiled HTML Help files
epub Enable E-Book support via app-text/ebook-tools
image-backend Enable image viewing support
markdown Enable Markdown support via app-text/discount
mobi Enable mobipocket support
mobile Enable Plasma mobile support
plucker Enable Plucker E-Book for Palm OS devices support
share Enable support for a share menu using kde-frameworks/purpose
speech Enable text-to-speech support

pimcommon

designer Build plugins for dev-qt/designer

spectacle

kipi Enable support for the KDE Image Plugin Interface
share Enable support for a share menu using kde-frameworks/purpose

step

qalculate Enable the libqalculate library for unit conversion

kde-frameworks

frameworkintegration

appstream Enable AppStream software metadata support

kconfigwidgets

man Build and install man pages

kded

man Build and install man pages

kdesignerplugin

designer Build KF5 widgets plugin for QtDesigner
webkit Build kdewebkit plugin for QtDesigner

kfilemetadata

epub Enable support for reading EPUB ebook metadata
office Enable support for reading ODF and OOXML metadata

kimageformats

eps Support the EPS graphics file format

kinit

caps Capabilities support for improved security and better OOM handling
man Build and install man pages

kio

kwallet Enable permanent storage of passwords for kpasswdserver with kde-frameworks/kwallet

knotifications

phonon Play notification sounds via media-libs/phonon instead of media-libs/libcanberra
speech Enable text-to-speech notification support

knotifyconfig

phonon Add sound support via media-libs/phonon

kpackage

man Build and install man pages

kservice

man Build and install man pages

ktexteditor

editorconfig Enable support for EditorConfig configuration files

ktextwidgets

speech Enable text-to-speech support

kwallet

gpg Support wallets with GnuPG encryption in addition to the default blowfish-encrypted file
man Build and install man pages

kxmlgui

attica Enable support for kde-frameworks/attica

networkmanager-qt

teamd Enable Teamd control support

plasma

gles2 Use GLES 2.0 or later instead of full OpenGL

prison

qml Enable QML/QtQuick support via dev-qt/qtdeclarative

purpose

kaccounts Enable support for system-wide defined KAccounts

sonnet

aspell Enable the app-text/aspell spell-checking backend
hunspell Enable the app-text/hunspell spell-checking backend

kde-misc

kdeconnect

app Enable experimental kcapp frontend
mousepad Enable remote mousepad plugin using x11-libs/libfakekey
wayland Enable kwin_wayland support for mousepad plugin using kde-frameworks/kwayland

kimtoy

scim Enable Smart Common Input Method support

kio-gdrive

kaccounts Use kde-apps/kaccounts-integration backend (default) instead of dev-libs/qtkeychain

kmarkdownwebview

webkit Use dev-qt/qtwebkit instead of dev-qt/qtwebengine

tellico

discid Add support for reading disc IDs from audio CDs

kde-plasma

kde-cli-tools

kdesu Build graphical frontend for kde-frameworks/kdesu

kdeplasma-addons

share Enable applet for quickly sharing data to a variety of sources
webengine Enable dictionary and web browser applets using dev-qt/qtwebengine

kinfocenter

gles2 Show OpenGL ES information in kinfocenter
pci Show advanced PCI information

kmenuedit

hotkeys Enable support for hotkey editing

kwin

gles2 Use OpenGL ES 2 instead of full GL
multimedia Enable effect video button in desktop effects KCM

libksysguard

detailedmemory Enable display of detailed memory information using dev-qt/qtwebkit.
webkit Enable display of detailed memory information using dev-qt/qtwebkit.

plasma-desktop

appstream Enable AppStream software metadata support
ibus Use ibus input method via app-i18n/ibus
mouse Enable mouse KCM
scim Enable applets that use app-i18n/scim
touchpad Enable touchpad KCM

plasma-meta

browser-integration Enable integration with Chrome/Firefox with browser extensions
crypt Pull in kde-plasma/plasma-vault for encrypted vaults integration
display-manager Pull in a graphical display manager
grub Pull in Breeze theme for sys-boot/grub
gtk Enable Breeze widget style and KCM for GTK2 and GTK3
legacy-systray Add support for GTK+ applications using legacy xembed systray icons
pam Enable support for kwallet auto-unlocking
plymouth Pull in Breeze theme for sys-boot/plymouth
pulseaudio Install Plasma applet for PulseAudio volume management
sddm Pull in the x11-misc/sddm display manager and KCM
sdk Pull in kde-plasma/plasma-sdk for Plasma development
wallpapers Install wallpapers for the Plasma Workspace

plasma-nm

modemmanager Enable support for mobile broadband devices
openconnect Build support for the OpenConnect VPN client
teamd Enable Teamd control support

plasma-workspace

appstream Enable AppStream software metadata support
geolocation Enables dataengine providing location information
prison Enable support for barcodes/QRcodes
qalculate Enable Qalculate runner using sci-libs/libqalculate

powerdevil

brightness-control Enable screen brightness control using app-misc/ddcutil
consolekit Enable sys-auth/consolekit support instead of logind session tracking
wireless Enable wireless energy saving actions via kde-frameworks/bluez-qt and kde-frameworks/networkmanager-qt

systemsettings

classic Enable classic mode plugin, requires kde-frameworks/khtml

lxde-base

lxdm

consolekit Enables support for authorization using consolekit
gtk3 Use GTK+3 instead of 2

lxterminal

gtk3 Use GTK+3 instead of GTK+2

lxqt-base

lxqt-config

monitor Build monitor settings tool

lxqt-meta

about Install lxqt-base/lxqt-about
admin Install lxqt-base/lxqt-admin
filemanager Install x11-misc/pcmanfm-qtfile manager
lightdm Install x11-misc/lightdmdisplay manager
lximage Install media-gfx/lximage-qtimage viewer
minimal Do not install x11-wm/openboxwindow manager
powermanagement Install lxqt-base/lxqt-powermanagement package
processviewer Install x11-misc/qps package
screenshot Install x11-misc/screengrab package
sddm Install x11-misc/sddm display manager
ssh-askpass Install lxqt-base/lxqt-openssh-askpass user password prompt tool
sudo Install lxqt-base/lxqt-sudo
terminal Install x11-terms/qterminal package

lxqt-panel

clock Build clock plugin
colorpicker Build colorpicker plugin
cpuload Build cpuload plugin
desktopswitch Build desktopswitch plugin
directorymenu Build directorymenu plugin
dom Build dom plugin
kbindicator Build kbindicator plugin
mainmenu Build mainmenu plugin
mount Build mount plugin
networkmonitor Build networkmonitor plugin
quicklaunch Build quicklaunch plugin
sensors Build sensors plugin
showdesktop Build showdesktop plugin
spacer Build spacer plugin
statusnotifier Build statusnotifier plugin
sysstat Build sysstat plugin
taskbar Build taskbar plugin
tray Build tray plugin
volume Build volume plugin
worldclock Build worldclock plugin

lxqt-session

themes Install LXQt themes and graphics

mail-client

alot

doc Install user manual and API documentation

alpine

chappa enhance alpine by applying Eduardo Chappa's patches
onlyalpine installs only the alpine binary, so it does not collied with pico and/or pine
passfile Adds support for caching passwords into a file between sessions
smime Enable support for S/MIME

balsa

crypt Adds support for GnuPG encryption
rubrica Adds support for rubrica addressbook

claws-mail

archive Enable archiving plugin
bogofilter Build mail-filter/bogofilter plugin
dillo Enable dillo html viewer plugin
gdata Enable plugin for access to Google data providers
gtk3 Build support for GTK+3
libcanberra Enable sound notification in connection with USE=notification
libindicate Enable notification through DBUS in connection with USE=notification
libnotify Enable notification on the desktop in connection with USE=notification
notification Notification for new mail in different way, see also USE flags libcanberra, libindicate and libnotify
pgp Enable PGP support
sieve Build plugin for sieve filter support
smime Build plugin for S/MIME support
spam-report Enable plugin for spam reporting to various services
spamassassin Build mail-filter/spamassassin plugin
valgrind Add support for memory debugging using valgrind

evolution

archive Enable archives support in attachments via app-arch/gnome-autoar
bogofilter Build mail-filter/bogofilter plugin
crypt Enable GPG encryption support using app-crypt/gnupg and app-crypt/pinentry
geolocation Enable support for displaying contacts on a map inside evolution using media-libs/libchamplain
highlight Enable text highlighting plugin
ldap Enable support for fetching contacts from an LDAP or Active Directory server using net-nds/openldap
spamassassin Build mail-filter/spamassassin plugin
weather Enable optional weather calendar support
ytnef Enable optional TNEF attachments parser support using net-mail/ytnef

mail-notification

sylpheed Enable support for MH mailboxes used by mail-client/sylpheed

mutt

berkdb Enable sys-libs/db database backend for header caching
crypt Add support for encryption -- using mcrypt or gpg where applicable
gdbm Enable sys-libs/gdbm database backend for header caching
gpg Enable support for app-crypt/gpgme
gpgme Build gpgme backend to support S/MIME, PGP/MIME and traditional/inline PGP
hcache Enable header cache, one database backend needs to be enabled
lmdb Enable dev-db/lmdb database backend for header caching
notmuch Enable support for net-mail/notmuch
pgp_classic Build classic_pgp backend to support PGP/MIME and traditional/inline PGP
pop Enable support for POP3 mailboxes
smime Enable support for smime
smime_classic Build classic_smime backend to support S/MIME
smtp Enable support for direct SMTP delivery
tokyocabinet Enable dev-db/tokyocabinet database backend for header caching

nail

kerberos If network is enabled, this adds support for GSSAPI login on IMAP through virtual/krb5.
net Enable support for network protocols (POP, IMAP and SMTP). If you only need to send mail with the local Transport Agent, disabling this will get you support for only /usr/sbin/sendmail call.
ssl If network is enabled, this adds support for S/MIME and SSL/TLS-powered protocols through dev-libs/openssl.

neomutt

berkdb Enable BDB (Berkley DB) backend for header caching
crypt Add support for encryption -- using mcrypt or gpg where applicable
gdbm Enable GDBM (GNU dbm) backend for header caching
gpg Enable support for app-crypt/gpgme
gpgme Build gpgme backend to support S/MIME, PGP/MIME and traditional/inline PGP
kyotocabinet Enable Kyoto Cabinet database backend for header caching
lmdb Enable LMDB (Lightning Memory-Mapped Database) backend for header caching
notmuch Enable support for net-mail/notmuch
pgp_classic Build classic_pgp backend to support PGP/MIME and traditional/inline PGP
qdbm Enable QDBM (Quicker Database Manager) database backend for header caching
smime Enable support for smime
smime_classic Build classic_smime backend to support S/MIME
tokyocabinet Enable Tokyo Cabinet database backend for header caching

roundcube

change-password Allow users to change passwords through Roundcube
enigma Add dependencies to support server-side GnuPG signing and/or encryption through the enigma plugin
ldap Add dependencies to support connecting to an LDAP address book server
managesieve Add dependencies to support the sieverules plugin

sylpheed

oniguruma Use dev-libs/oniguruma for regular expression

thunderbird

bindist Disable official Thunderbird branding (icons, name) which are not binary-redistributable according to upstream.
clang Use Clang compiler instead of GCC
crypt Enable encryption support with enigmail
custom-optimization Build with user-specified compiler optimizations (-Os, -O0, -O1, -O2, -O3) from CFLAGS (unsupported)
gtk2 Use the cairo-gtk2 rendering engine instead of the default cairo-gtk3
lightning Enable app-global calendar support (note 38.0 and above bundles calendar support when this flag is off)
minimal Remove the software development kit and headers
mozdom Enable Mozilla's DOM inspector
rust Enable support for using rust compiler (experimental)
system-cairo Use the system-wide x11-libs/cairo instead of bundled.
system-harfbuzz Use the system-wide media-libs/harfbuzz and media-gfx/graphite2 instead of bundled.
system-icu Use the system-wide dev-libs/icu instead of bundled.
system-jpeg Use the system-wide media-libs/libjpeg-turbo instead of bundled.
system-libevent Use the system-wide dev-libs/libevent instead of bundled.
system-libvpx Use the system-wide media-libs/libvpx instead of bundled.
system-sqlite Use the system-wide dev-db/sqlite installation with secure-delete enabled

thunderbird-bin

crashreporter Enable crash reporter for bugs

trojita

password Store passwords securely via dev-libs/qtkeychain

mail-filter

MailScanner

exim Set mail-mta/exim to used MTA
postfix Set mail-mta/postfix to used MTA
spamassassin Enable usage of mail-filter/spamassassin for spam protection

amavisd-new

courier Add courier support
dkim Add DomainKeys Identified Mail support
qmail Add qmail support
razor Add support for mail-filter/razor
spamassassin Add support for mail-filter/spamassassin
zmq Add support for zeromq sockets

ask

procmail Adds support for mail-filter/procmail

assp

spf Adds support for Sender Policy Framework
srs Adds support for Sender Rewriting Scheme

bogofilter

tokyocabinet Enable Tokyo Cabinet database support

clamassassin

clamd Use the app-antivirus/clamav daemon for virus checking
subject-rewrite Adds support for subject rewriting

dcc

rrdtool Enable net-analyzer/rrdtool interface scripts

dspam

daemon Enable support for DSPAM to run in --daemon mode
debug Enable debugging support (don't enable this unless something needs testing!)
domain-scale Build for domain scale setups - puts data to $HOME/data/domain.com/user
hash Enable support for the file-orientated hash driver
large-scale Build for large scale setups - puts data to $HOME/data/u/s/user
small-scale Build for small scale setups - puts data to $HOME/data/user
user-homedirs Build with user homedir support
virtual-users Build with virtual-users support

libmilter

poll Use poll instead of select

maildrop

authlib Add courier-authlib support
dovecot Add dovecot authentication support
tools Install maildirmake and deliverquota tools
trashquota Count deleted messages as part of the maildir quota

mimedefang

poll Use poll instead of select

opendkim

ldap Enable openldap as a dataset facilitator or keys, determining domains to sign for, and any other dataset that opendkim supports.
lmdb Add support for using dev-db/lmdb
lua Enables control over signature verification, filtering and policy to be controlled by user defined lua scripts.
memcached Add support for using dev-libs/libmemcached
opendbx Use opendbx backend to facilitate dataset driven OpenDKIM configuration options like stats, bodylengthdb, etc. against a wide variety of database types
poll Use poll() instead of select() for the provided asynchronous resolver library.
sasl Used to authenticate to a LDAP server in various ways if required.
unbound Use the unbound dnssec library to perform DKIM DNS queries.

opendmarc

reports Install the reports binaries: expire, import, reports, params
spf Use the mail-filter/libspf2 for Sender Policy Framework checking

opensmtpd-extras

filter-clamav filter for scanning with app-antivirus/clamav
filter-dkim-signer filter for adding DKIM signatures to outgoing messages
filter-dnsbl filter for checking hosts against the DNS black lists
filter-lua filter for interfacing with dev-lang/lua
filter-monkey filter for arbitrarily rejecting random emails
filter-pause filter to pause on new connections
filter-perl filter for interfacing with dev-lang/perl
filter-python filter for interfacing with dev-lang/python
filter-regex filter for regular expression matching
filter-spamassassin filter for scanning with mail-filter/spamassassin
filter-stub stub filter
filter-trace trace filter
filter-void void filter
queue-null null queue
queue-python queue for interfacing with dev-lang/python
queue-ram ram queue
queue-stub stub queue
scheduler-python schedulre for interfacing with python
scheduler-ram ram scheduler
scheduler-stub stub scheduler
table-ldap table for lookups with net-nds/openldap
table-mysql table for lookups with virtual/mysql
table-passwd table for lookups using /etc/passwd
table-postgres table for lookups with dev-db/postgresql
table-python table for interfacing with dev-lang/python
table-redis table for lookups with dev-db/redis
table-socketmap table for lookups using a socket map
table-sqlite table for lookups with dev-db/sqlite3
table-stub stub table

postfwd

tools Install additional tools for testing postfwd

postgrey

targrey Enables the targrey patch

rmilter

dkim Enable support for DomainKeys Identified Mail
memcached Enable support for memcached

rspamd

fann Enable neural network plugin (requires sci-mathematics/fann).
pcre2 Use dev-libs/libpcre2
torch Enable torch support. This is required for the neural module

spamassassin

cron Install a cron job to update SpamAssassin's rules daily.
qmail Build qmail functionality and docs

spamdyke

ssl Enables TLS protocol for spamdyke

zdkimfilter

debug Log process and signal information. Also leave the child process running for gdb examination.
opendbx An alternate statistics based storage engine.

mail-mta

courier

fax Enables fax support in the courier mail server
norewrite Prevents courier mail server from mangling virtual user addresses when sending
web Enable the web interface
webmail Enable the webmail interface

exim

arc Adds support for Authenticated Receive Chain (ARC)
dane Adds support for DNS-based Authentication of Named Entities
dcc Adds support for Distributed Checksum Clearinghouse (DCC)
dkim Adds support for DomainKeys Identified Mail (DKIM)
dlfunc Install local_scan.h header to compile separate dlfunc libraries
dmarc Adds support for DMARC
dnsdb Adds support for a DNS search for a record whose domain name is the supplied query
dovecot-sasl Adds support for Dovecot's authentication
dsn Adds support for Delivery Status Notifications (DSN)
exiscan-acl Patch providing support for content scanning
lmtp Adds support for lmtp
mbx Adds support for UW's mbx format
pkcs11 Require pkcs11 support in net-libs/gnutls with USE=gnutls
prdr Adds support for Per-Recipient Data Response
proxy Add support for being behind a proxy, such as HAProxy
redis Adds support for querying dev-db/redis
spf Adds support for Sender Policy Framework
srs Adds support for Sender Rewriting Scheme
tpda Adds support for Transport Post-Delivery Actions

msmtp

daemon Build/install msmtpd MTA daemon
mta Enable this to install as system-wide MTA

netqmail

authcram Enable AUTHCRAM support
gencertdaily Generate SSL certificates daily instead of hourly
highvolume Prepare netqmail for high volume servers

opensmtpd

mta Enable this to install as system-wide MTA

postfix

dovecot-sasl Enable net-mail/dovecot protocol version 1 (server only) SASL implementation
eai Add support for SMTPUTF8
ldap-bind Add support for binding to LDAP backend using dev-libs/cyrus-sasl
lmdb Add support for using dev-db/lmdb for lookup tables
memcached Add support for using net-misc/memcached for lookup tables
vda Add support for virtual delivery agent quota enforcing

qmail-ldap

cluster Enable this if you want to have cluster support in qmail-ldap
gencertdaily Generate SSL certificates daily instead of hourly
highvolume Prepare qmail for high volume servers
rfc2307 Add support for RFC2307 compliant uid/gid attributes
rfc822 Add support for RFC822 compliant mail attributes

qpsmtpd

postfix create user with permissions for proper postfix interaction

ssmtp

mta Install symlinks for sendmail-compatible MTA.

mate-base

caja

mate Install x11-themes/mate-icon-theme which is needed when this package is used in the MATE desktop environment.
packagekit Enable support for installing via app-admin/packagekit based on mimetype

mate

base Install base MATE Desktop applications that are recommended for the most common usage; for example, this installs the file manager. Disable this and other USE flags if you want a more minimal MATE Desktop.
extras Install additional MATE Desktop applications that are recommended for extended usage of the MATE Desktop as upstream sees it; for example, this installs MATE Desktop's office related applications. Disable this if you plan to use your own non-MATE Desktop alternatives or a custom mixture of MATE and non-MATE packages.
help Install gnome-extra/yelp to handle in application help menus and documentation browsing
notification Force notification daemon to default to MATE's notification daemon. Enabled by default. Disable if it causes conflicts with other installed desktop environments.
themes Install MATE Desktop's themes; if you use other themes, you can disable this to spare some space and time.

mate-applets-meta

appindicator Pull in mate-extra/mate-indicator-applet for AppIndicator applet
sensors Pull in mate-extra/mate-sensors-applet for hw sensors applet

mate-control-center

appindicator Add support for AppIndicator

mate-session-manager

xtrans Build with Xtrans support; WARNING: Disabling this flag will result in ICE binding on all interfaces

mate-extra

caja-extensions

cdr Add an extension to burn files to cds using app-cdr/brasero.
gajim Add an extension to support net-im/gajim.
gksu Add an extension to support opening files as root with x11-libs/gksu.
image-converter Add image conversion support.
mail Add an extension to support e-mail functionality.
open-terminal Add an extension to support an open terminal.
pidgin Add an extension to support net-im/pidgin
share Add an extension to support sharing files.
wallpaper Add an extension to support setting an image as the current wallpaper

mate-polkit

accountsservice Support extraction of data from AccountsService
appindicator Add support for AppIndicator

mate-power-manager

applet Enable building of the MATE applet.
pm-utils Adds support for suspend/resume using sys-power/upower-pm-utils instead of sys-power/upower

mate-screensaver

consolekit Enable support for sys-auth/consolekit

mate-utils

applet Enable the mate dictionary applet

media-fonts

corefonts

tahoma Also install the Tahoma font. Due to the lack of a free bold variant, this may render badly. See bug 184790.

culmus

ancient Install ancient semitic scripts
fancy Install fancy fonts
fontforge Use media-gfx/fontforge to build fonts from source
taamey Install taamey fonts

dejavu

fontforge Use media-gfx/fontforge to build fonts from source

fontawesome

otf Install the OpenType version of the font
ttf Install the TrueType version of the font

infinality-ultimate-meta

free Install fonts for the "free" preset
latin Install additional latin fonts
minimal Install a minimal set of fonts
ms Install (free) fonts for the "ms" preset

intlfonts

bdf Installs BDF fonts in addition to PCF

liberation-fonts

fontforge Use media-gfx/fontforge to build fonts from source

montecarlo

bdf Install BDF fonts in addition to PCF

mplus-outline-fonts

ipafont Generates new fonts merged with media-fonts/ja-ipafonts

sil-charis

compact Use more compactly spaced font

sil-gentium

compact Also install more compact version of the font.

terminus-font

a-like-o Changes view of letter 'a' - a looks like o (see homepage)
center-tilde Place the '~' character vertically centered on the line instead of to the top.
distinct-l ll2 variant with more distinctive l (lowercase L)
pcf Install Portable Compiled Font (PCF) (required for X11)
pcf-unicode-only Remove non-unicode PCF fonts that could be problematic. See bug #520222.
psf Install PC Screen Font (PSF) with unicode data (for linux console)
quote Changes view of quotes: symmetric ` and ' instead of asymmetric one (see homepage)
ru-dv Changes view of Russian letters 'de' and 've' (see homepage)
ru-g Changes view of Russian letter 'ge' (see homepage)
ru-i Changes view of Russian letter 'i' - not like Latin u, but like "mirrored" N (see homepage)
ru-k Changes view of Russian letter 'k' (see homepage)

unifont

fontforge Use media-gfx/fontforge to build fonts from source
utils Install unifont utilities

media-gfx

ahoviewer

libsecret Support password storing using libsecret
rar Rar archive support
zip Zip archive support

album

plugins Install optional plugins
themes Install optional themes

alembic

arnold Add support for arnold renderer (experimental)
boost Use dev-libs/boost library
examples Install alembic examples
hdf5 Add support sci-libs/hdf5
maya Compile Alembic plugin for Maya (experimental)
prman Compile Alembic plugin for Renderman (experimental)
pyalembic Build pyalembic python bindings (needs dev-python/pyilmbase)
python Build pyalembic python bindings (needs dev-python/pyilmbase)
test Build and run the test-suite
zlib Use sys-libs/zlib for compressions

apngasm

7z Enable support for 7zip compression
zopfli Enable support for Zopfli compression

asymptote

boehm-gc Enables using the Boehm-Demers-Weiser conservative garbage collector
offscreen Enables off-screen rendering
sigsegv Enables using dev-libs/libsigsegv

blender

boost Enable features depending on boost.
bullet Enable Bullet (Physics Engine).
collada Add support for Collada interchange format through media-libs/opencollada.
colorio Enable OpenColorIO color management through media-libs/opencolorio.
cuda Build cycles renderer with nVidia CUDA support.
cycles Build cycles renderer (requires media-libs/openimageio and dev-libs/boost).
dds Adds DDS textures support to Blender.
doc Build C and Python API documentation directly from the source code.
elbeem Adds surface fluid simulation to Blender using El'Beem library.
game-engine Adds Game Engine support to Blender.
headless Build without graphical support (renderfarm, server mode only).
llvm Enable features depending on llvm.
man Build and install man pages.
ndof Enable NDOF input devices (SpaceNavigator and friends).
opencl Allow OpenCL Graphics Acceleration. This may require extra graphics card drivers.
openimageio Enable OpenImageIO Support
opennl Enable use of Open Numerical Library
opensubdiv Add rendering support form OpenSubdiv from Dreamworks Animation through media-libs/opensubdiv.
openvdb Add GPU preview rendering. Only works with nVidia cards.
osl Add support for OpenShadingLanguage scripting.
player Build the Blender Player. THis requires the Game engine.
redcode This flag add support for RED CODE camera digital format (5K HD images *.r3d) - EXPERIMENTAL.
test Build the provided unit tests.
valgrind Add support for memory debugging using dev-util/valgrind

comix

rar Pulls app-arch/unrar for rar file support

cura

usb Access 3D printers via USB

darktable

colord Support color management using x11-misc/colord
flickr Add support for uploading photos to flickr
geolocation Enable geotagging support
kwallet Enable encrypted storage of passwords with kde-frameworks/kwallet
opencl Enable opencl support
pax_kernel Triggers paxmarking of main darktable binary

digikam

addressbook Enable akonadi contact integration
kipi Enable support for media-plugins/kipi-plugins
lensfun Enable support for media-libs/lensfun
marble Enable support for geolocation using kde-apps/marble
mediaplayer Enable support for media player using media-libs/qtav
panorama Build the panorama plugin which requires media-gfx/hugin
semantic-desktop Enable kde-frameworks/kfilemetadata support

eog-plugins

map Enable world map display using media-libs/libchamplain
picasa Enable uploading to Google's Picasa Web Albums

exact-image

swig Adds Swig support dev-lang/swig

exiv2

webready Support reading metadata over the internet

fbida

X Install the Motif based image viewer "ida"
fbcon Install the framebuffer image viewer "fbi"
ghostscript Install the framebuffer ghostscript viewer "fbgs"

fim

bmp Enable BMP file support
dia Enable DIA file support via app-office/dia
imagemagick Use convert from media-gfx/imagemagick as fallback file opener
pcx Enable PCX file support
xfig Enable FIG file support via media-gfx/xfig

fontforge

truetype-debugger Enable truetype debugger in fontforge

fotowall

webcam Enable webcam support

freewrl

glew Enable glew extensions
java Build and install java EAI/SAI support library
libeai Build EAI C library
opencl Enable OpenCL support
osc Allows for OSC-based control and communication between multiple freewrl instances
rbp Enable support for Rigid Body Physics

geeqie

ffmpegthumbnailer Enable video thumbnail support with media-video/ffmpegthumbnailer
gpu-accel Enable GPU acceleration support - experimental
gtk3 Link against x11-libs/gtk+:3 instead of x11-libs/gtk+:2
map Enable items map display - experimental

gimp

heif Enable support for ISO/IEC 23008-12:2017 HEIF files
smp Enable support for multiprocessors
vector-icons Enable support for vector icons (experimental)

gmic

cli Build CLI interface
opencv Enable support for webcams using the OpenCV library

gnome-photos

flickr Ensure runtime Flickr support

graphicsmagick

fpx Enable FlashPix support with media-libs/libfpx
modules Compile graphicsmagick with dynamically loadable modules
q16 Set storage quantum size to 16 (~2*memory)
q32 Set storage quantum size to 32 (~5*memory)

graphviz

X Builds lefty front-end, builds plugin -Txlib, and enables support for x11 in various other modules (needs cairo)
devil Enables DevIL output plugin -Tdevil
gdk-pixbuf Enables gdk-pixbuf2 plugin
gtk Enables gtk+ output plugin -Tgtk (needs cairo)
gts Enables support for gts
lasi Enables PostScript output via media-libs/lasi, for plugin -Tlasi (needs cairo)

gthumb

colord Use x11-misc/colord for color management
http Enable webservice integration through net-libs/libsoup
json Compile code that uses the libjson-glib library
slideshow Enable slideshow plugin

hugin

sift automatically align images with media-gfx/autopano-sift-C

imagemagick

corefonts Use media-fonts/corefonts which is required by some commands
fpx Enable media-libs/libfpx support
hdri Enable High Dynamic Range Images formats
heif Enable support for ISO/IEC 23008-12:2017 HEIF/HEIC image format using media-libs/libheif
lqr Enable experimental liquid rescale support using media-libs/liblqr
opencl Enable OpenCL support
pango Enable Pango support using x11-libs/pango
q32 Set quantum depth value to 32
q8 Set quantum depth value to 8

inkscape

cdr Enable support for CorelDRAW Diagrams
dia pull in app-office/dia for dia import extension
inkjar Enable support for OpenOffice.org SVG jar files
latex pull in dependencies for LaTeX formulas
visio Enable support for Microsoft Visio Diagrams
wpg Enable support for WordPerfect Graphics

iscan-plugin-gt-f500

minimal Install the firmware only, and not the plugin.

jpeg2ps

metric Default to A4 paper size

kphotoalbum

kipi Support for the KDE Image Plugin Interface
map Enable map display support using kde-apps/libkgeomap

krita

color-management Enable color management via media-libs/opencolorio
heif Enable support for ISO/IEC 23008-12:2017 HEIF/HEIC image format using media-libs/libheif
qtmedia Enable sound support for animations via dev-qt/qtmultimedia
vc Enable support for dev-libs/vc, could be a significant speed boost

librecad

3d Require all 2D coordinates stored as 3D
tools Build additional tool programs: tff2lff

luminance-hdr

fits Enable support for the FITS format

mandelbulber

opencl Enable GPU rendering support using OpenCL

nomacs

opencv Build support for media-libs/opencv

nvidia-texture-tools

cg Enable NVIDIA C graphics compiler toolkit plug-in
cuda Enable NVIDIA CUDA toolkit support
glew Enable support for The OpenGL Extension Wrangler Library (media-libs/glew)

openclipart

gzip Compresses clip art using gzip

openexr_viewers

cg Add support for nvidia's cg shaders

openvdb

abi3-compat Disables newer features to maintain compatibility with ABI3. Enabled by default.
abi4-compat Disables newer features to maintain compatibility with ABI4. Enabled by default.

photoqt

devil Support additional image formats using media-libs/devil
exiv2 Use media-gfx/exiv2 as optional dependency
freeimage Support additional iamge formats using media-libs/freeimage

pngcrush

system-libs Use libpng and libz provided by system

potrace

metric default to a4 paper size and metric measurement

povray

io-restrictions POV-Ray's mechanism for control of I/O operations
mkl Enable support for Intel Vector Math Library, part of sci-libs/mkl

pqiv

archive Enable support for images in archives and cbX comic book files

pstoedit

emf Enable media-libs/libemf support
flash Enable media-libs/ming SWF support
pptx Enable support for generating PowerPoint pptx files

qimgv

video Add support for gif/webm playback via libmpv

qiv

magic Use libmagic to determine mimetypes

sigal

s3 Enables support for the Amazon S3 service.

simple-scan

colord Support color management using x11-misc/colord

slic3r

gui Enable GUI

splashutils

fbcondecor Support for the fbcondecor kernel patch.

ufraw

contrast enable contrast setting option
fits Enable support for the FITS image format through sci-libs/cfitsio
timezone enable DST correction for file timestamps

xpaint

pgf Support for loading PGF images

xsane

ocr Enable support for Optical Character Recognition reader

yafaray

blender Install addon for media-gfx/blender
fastmath Enable mathematic approximations to make code faster
fasttrig Enable trigonometric approximations to make code faster
opencv Use media-libs/opencv

media-libs

a52dec

djbfft Prefer D.J. Bernstein's library for fourier transforms

allegro

dumb Enable media-libs/dumb module library support
physfs Enable physfs support
vga Enables the VGA graphics driver

alsa-lib

alisp Enable support for ALISP (ALSA LISP) interpreter for advanced features.
thread-safety thread-safe API functions

alure

dumb Enable media-libs/dumb module library support
fluidsynth Enables Fluidsynth MIDI software synthesis

assimp

samples Build viewer library
tools Build assimp tool binary

aubio

double-precision Compile in double precision mode.

avidemux-core

nvenc Adds support for NVIDIA Encoder (NVENC) API for hardware accelerated encoding on NVIDIA cards.
system-ffmpeg Use the ffmpeg provided by the system.

avidemux-plugins

aften Enable A/52 (AC-3) audio encoder support.
amr Enable Adaptive Multi-Rate format support via media-libs/opencore-amr.
dcaenc Enable DTS Coherent Acoustics audio encoder support via media-sound/dcaenc.
fdk Adds support for encoding AAC using media-libs/fdk-aac.
fribidi Enable unicode bidirectional algorithm support via dev-libs/fribidi.
nvenc Adds support for NVIDIA Encoder (NVENC) API for hardware accelerated encoding on NVIDIA cards.
twolame Enable TwoLAME support via media-sound/twolame, an optimised MPEG Audio Layer 2 (MP2) encoder.
vpx Enable WebM VP8 Codec SDK support via media-libs/libvpx.
x265 Enables HEVC support with media-libs/x265.

babl

cpu_flags_x86_f16c Take advantage of CPU feature f16c

cal3d

16bit-indices Enables use of 16bit indices

chromaprint

tools Build and install fpcalc and fpcollect tools

clutter

egl Enable EGL backend.
gtk Use gdk-pixbuf from x11-libs/gtk+ as image rendering backend

cogl

gles2 Enable OpenGL ES 2.0 support
kms Enable KMS support.
pango Build cogl-pango library for x11-libs/pango integration

coin

qthelp Build API documentation in QtHelp format
simage Texture loading via media-libs/simage library

dav1d

10bit Add support for building 10-bit AV1.
8bit Add support for decoding 8-bit AV1.
asm Enable custom x86 assembly for faster decoding.

devil

allegro Add support for Allegro
nvtt Add support for media-gfx/nvidia-texture-tools

esdl

image Enable image support

faad2

digitalradio Digital Radio Mondiale (warning: disables other decoders)

flickcurl

raptor Use media-libs/raptor for proper RDF serializing

fontconfig-infinality

nyx Additional style using croscorefonts

freetype

adobe-cff Use Adobe CFF as default font-renderer
bindist Disable ClearType support (see http://freetype.org/patents.html)
bzip2 Support bzip2 compressed PCF fonts.
cleartype_hinting New bytecode hinting mode for TrueType fonts that activates subpixel hinting (a.k.a. ClearType hinting) by default
fontforge Install internal headers required for TrueType debugger in media-gfx/fontforge (built with USE=truetype-debugger)
harfbuzz Use media-libs/harfbuzz for auto-hinting OpenType fonts. WARNING: may trigger circular dependencies!
infinality Enable infinality options for improved LCD filtering
utils Install utilities and examples from ft2demos

freeverb3

audacious Build Audacious plugin
forcefpu Disable assembly code
plugdouble Build plugins in double precision mode (default is float)

ganv

fdgl Use experimental force-directed graph layout

gd

webp Enable support for the webp format

gegl

lensfun Enable support for media-libs/lensfun.
umfpack Enable sparse solving via sci-libs/umfpack.

giflib

rle Build converters for RLE format (utah raster toolkit)

gmtk

dconf Enable support for gnome-base/dconf

grilo

network Enable network access for media discovery using net-libs/libsoup
playlist Enable support for playlists through dev-libs/totem-pl-parser

gst-plugins-bad

bzip2 Enable bzip2 encoder/decoder plugin
egl Enable EGL support
gles2 Enable GLES2 support

gst-plugins-base

X Enable ximagesink and xvimagesink plugins; build GLX platform support if USE=opengl is enabled; build x11 windowing system support if USE=egl is enabled
egl Enable EGL platform support
gbm Enable Graphics Buffer Manager based EGL windowing system support (requires egl and at least one of gles or opengl)
gles2 Enable OpenGL library and plugin via GLESv2 API (requires egl)
ivorbis Enable integer based vorbis decoder
opengl Enable OpenGL library and plugin via desktop OpenGL API
pango Enable pango GStreamer plugin
wayland Enable Wayland EGL windowing system support (requires egl and at least one of gles2 or opengl)

gstreamer

orc Disable some PaX memory protections to allow plugins that use dev-lang/orc for runtime optimization to be used on hardened PaX systems
unwind Enable sys-libs/libunwind usage for better backtrace support in leaks tracer module

harfbuzz

glib Compile with GLib Unicode support
graphite Use graphite to render complex non-Roman writing systems

imlib2

shm Use MIT shared memory support for X image transfer.

leptonica

utils Install command-line utilities

libafterimage

shaping Use MIT shaped X windows extention.
shm Use MIT shared memory extention for X image transfer.

libass

harfbuzz Enables OpenType shaping via media-libs/harfbuzz.

libbdplus

aacs Add support for decryption of AACS

libbluray

aacs Add support for decryption of AACS
bdplus Use media-libs/libbdplus for BD+ decryption
java Add support for BD-J
utils Install command-line utilities and examples

libcanberra

alsa Enables ALSA sound driver.
gstreamer Enables gstreamer sound driver. Not useful when alsa or pulseaudio is available.
gtk Enables building of gtk+ helper library, gtk+ runtime sound effects and the canberra-gtk-play utility. To enable the gtk+ sound effects add canberra-gtk-module to the colon separated list of modules in the GTK_MODULES environment variable.
gtk3 Enables building of gtk+3 helper library, gtk+3 runtime sound effects and the canberra-gtk-play utility. To enable the gtk+3 sound effects add canberra-gtk-module to the colon separated list of modules in the GTK_MODULES environment variable.
pulseaudio Enables PulseAudio sound driver that should be able to support positional event sounds. This is the preferred choice for best sound events experience and picked by default if compiled in and possible to use at runtime.
sound Install x11-themes/sound-theme-freedesktop to get sounds on Gnome and Xfce.
tdb Enables Trivial Database support for caching purposes.

libextractor

apparmor Enable apparmor support using sys-libs/libapparmor
archive Enable archive support using app-arch/libarchive
gsf Enable OLE2 (MS Office) plug-in support using gnome-extra/libgsf
magic Enable magic support using sys-apps/file
midi Enable MIDI support through media-libs/libsmf

libffado

test-programs Install standalone test programs

libggi

vis Enables sparc vis support for libggi

libgphoto2

serial Enable serial port support

libgpod

gtk Enable ArtworkDB support

libgroove

chromaprint Enable audio fingerprinting using media-libs/chromaprint.
loudness Enable loudness detection according to the EBU R128 standard using media-libs/libebur128.
sound Enable audio playing.

liblastfm

fingerprint Build the lastfm-fingerprint library

libmp4v2

utils Install command-line utilities

libmypaint

gegl Add support for media-libs/gegl

libopenglrecorder

openh264 Enable H.264 support using media-libs/openh264
vpx Enable VP8/VP9 codec support via media-libs/libvpx

libpagemaker

tools Build command line file format conversion tools

libpng

apng support unofficial APNG (Animated PNG) spec

libpostproc

pic Force shared libraries to be built as PIC (this is slower).

libprojectm

gles2 Provide support for OpenGL ES 2 and 3

libquicktime

schroedinger Enable Dirac video support (an advanced royalty-free video compression format) via libschroedinger (high-speed implementation in C of the Dirac codec)

libraw

demosaic Enable support for external interpolation algorithms

libsdl

joystick Control joystick support (disable at your own risk)
sound Control audio support (disable at your own risk)
tslib Build with tslib support for touchscreen devices
video Control video support (disable at your own risk)

libsdl2

gles include OpenGL ES support
haptic Enable the haptic (force feedback) subsystem
joystick Control joystick support (disable at your own risk)
kms Build the KMSDRM video driver
sound Control audio support (disable at your own risk)
tslib Build with tslib support for touchscreen devices
video Control video support (disable at your own risk)
vulkan Enable Vulkan support

libvisio

tools Build conversion tools

libvpx

highbitdepth Enable 10 and 12 bit support for VP9.
postproc Enable additional post processing filters
svc Enable spatial-svc support (experimental)

libwebp

experimental Build with -DWEBP_EXPERIMENTAL_FEATURES
swap-16bit-csp Enable byte swapping for 16 bit colorspace

libyami

dmabuf Enable dma_buf buffer sharing.
egl Enable EGL support.
md5 Add support for generating md5 sums for each frame.
v4l Add support for V4L2 hardware codecs.

libzmf

tools Build conversion tools

lilv

dyn-manifest Add LV2 Dynamic Manifest support. See http://lv2plug.in/ns/ext/dynmanifest/

lv2

plugins Enables examples plugins.

lvtk

gtk2 Enable x11-libs/gtk+:2 based GUI support
tools Compile and install ttl2c tool

mediastreamer

amr Use of AMR Narrow Band codec plugin
filters Enable compilation of filters
g726 Support g726 codec
g729 Use g726 codec plugin
ilbc Use of iLBC (RFC3951) codec plugin
ntp-timestamp Turn on NTP timestamping on received packet
ortp Enable usage of net-libs/ortp
pcap Enable usage of net-libs/libpcap
silk Use silk (skype protocol) codec plugin
video Enable video support

mesa

bindist Disable patent-encumbered ARB_texture_float, EXT_texture_shared_exponent, and EXT_packed_float extensions.
classic Build drivers based on the classic architecture.
d3d9 Enable Direct 3D9 API through Nine state tracker. Can be used together with patched wine.
dri3 Enable DRI3 support.
egl Enable EGL support.
gallium Build drivers based on Gallium3D, the new architecture for 3D graphics drivers.
gbm Enable the Graphics Buffer Manager for EGL on KMS.
gles1 Enable GLESv1 support.
gles2 Enable GLESv2 support.
llvm Enable LLVM backend for Gallium3D.
opencl Enable the Clover Gallium OpenCL state tracker.
openmax Enable OpenMAX video decode/encode acceleration for Gallium3D.
osmesa Build the Mesa library for off-screen rendering.
pax_kernel Enable if the user plans to run the package under a pax enabled hardened kernel
pic disable optimized assembly code that is not PIC friendly
unwind Add support for stack trace unwinding and function name resolution
valgrind Compile in valgrind memory hints
vdpau Enable the VDPAU acceleration interface for the Gallium3D Video Layer.
vulkan Enable Vulkan drivers
wayland Enable support for dev-libs/wayland
xa Enable the XA (X Acceleration) API for Gallium3D.
xvmc Enable the XvMC acceleration interface for the Gallium3D Video Layer.

mlt

compressed-lumas Compress the luma files in png.
frei0r Build the module for media-plugins/frei0r-plugins
kdenlive Build support for kde-apps/kdenlive
lua Build SWIG bindings for Lua
melt Build the melt commandline tool
opencv Build motion tracking module using media-libs/opencv
python Build SWIG bindings for Python
rtaudio Builds rtaudio consumer for native audio support on multiple platforms.
ruby Build SWIG bindings for Ruby

netpbm

rle Build converters for the RLE format (utah raster toolkit)

opencv

contrib Install user contributed scripts from opencv_contrib (Experimental!)
contrib_cvv CVV module requires Qt5
contrib_dnn DNN module contrib requires tiny dnn
contrib_hdf HDF module requires sci-libs/hdf5
contrib_sfm SFM module requires eigen, gflags, and glog
contrib_xfeatures2d Enables xfeatures2d and autodownload of samples in contrib
cuda Enable NVIDIA Cuda computations support (Experimental!)
dnn_samples Download dnn caffeemodel samples
eigen Enable usage of dev-cpp/eigen for computations
gdal Enable support for sci-libs/gdal library
gflags Use Google's C++ argument parsing library
glog Use Google's C++ loggin library
opencl Add support for OpenCL
tesseract Use Google's OCR Engine
testprograms Build and install programs for testing OpenCV (performance)
vtk Build new 3D visualization module viz based on sci-libs/vtk

openh264

plugin Install the Gecko Media Plugin (GMP) for use with Mozilla packages
utils Install the CLI encoder and decoder utilities

openimageio

colorio Use media-libs/opencolorio
cpu_flags_x86_avx512f SIMD Optimization
cpu_flags_x86_f16c SIMD Optimization
field3d Use media-libs/Field3D
opencv Use media-libs/opencv
ptex Use media-libs/ptex

opensubdiv

cuda Enable NVIDIA CUDA Toolkit support through dev-util/nvidia-cuda-toolkit.
opencl Enable OpenCL support through virtual/opencl.
ptex Adds support for faster per-face texture mapping through media-libs/ptex.
tbb Enable multithreading with the Intel Threads Building Blocks through dev-cpp/tbb.

opus

ambisonics Enable ambisonics support (experimental).
custom-modes Build with custom-modes.

opusfile

fixed-point Enable fixed-point arithmetic operations
float Enable floating point arithmetic operations
http Enable http connections

osl

cpu_flags_x86_avx512f SIMD Optimization
cpu_flags_x86_f16c SIMD Optimization
partio Use media-libs/partio

phonon

designer Install plugin for dev-qt/designer
vlc Install VLC Phonon backend

phonon-gstreamer

network Enable network streaming support via libsoup

portmidi

test-programs Install various example programs

qtav

gui Build a video player gui

quvi

json Enable support for JSON output

raptor

json Enable support for JSON parsing

raspberrypi-userland-bin

hardfp Use armv6 hardfp ABI

sdif

ftruncate Enables usage of ftruncate v. truncate

sdl-mixer

fluidsynth Use media-sound/fluidsynth for MIDI support
midi basic support for MIDI files
mod basic support for MOD files
playtools Install playwave and playmus tools (useful for testing)
smpeg Use media-libs/smpeg for MP3 support
wav support WAVE files

sdl-sound

physfs Enable physfs support

sdl2-image

webp support loading WEBP images

sdl2-mixer

fluidsynth Use media-sound/fluidsynth for MIDI support
midi basic support for MIDI files
mod basic support for MOD files
playtools Install playwave and playmus tools (useful for testing)
smpeg Use media-libs/smpeg for MP3 support
tremor enable OGG Vorbis music via libtremor
wav support WAVE files

sge

image enable sdl-image support

spandsp

fixed-point Enable fixed point support

speex

utils Enables speex commandline utilities (speexenc, speexdec).
vbr Enable VBR support.

svgalib

kernel-helper Build the helper kernel module

taglib

boost Use dev-libs/boost instead of GCC built-ins

tiff

zstd Enable zstd compression support.

tremor

low-accuracy enable 32bit only multiply operations

urt

tools Install tools

vigra

valgrind Enable valgrind in make check

vulkan-loader

layers Include the vulkan layers

waffle

egl Enable EGL support
gbm Enable support for the Generic Buffer Manager (gbm)
wayland Enable Wayland support

x264

10bit Set output bit depth to 10, this may not be compatible with all decoders
interlaced enable interlaced encoding support, this can decrease encoding speed by up to 2%
opencl Add support for OpenCL.
pic disable optimized assembly code that is not PIC friendly

x265

10bit Add support for producing 10bits HEVC.
12bit Add support for producing 12bits HEVC.
numa Build with support for NUMA nodes.
pic Disable optimized assembly code that is not PIC friendly
power8 Enable support for Power 8 assembly optimizations.

xine-lib

bluray Enable playback of Blu-ray filesystems using media-libs/libbluray
dxr3 Enable support for DXR3 mpeg acceleration cards.
flac Build the media-libs/flac based FLAC demuxer and decoder. This flag is not needed for playing FLAC content, neither standalone nor in Ogg container (OggFLAC), but might have better support for exotic features like 24-bit samples or 96kHz sample rates.
gtk Build the gdkpixbuf-based image decoder plugin.
imagemagick Build the ImageMagick-based image decoder plugin.
mad Build the media-libs/libmad based mp3 decoder. This mp3 decoder has superior support compared to the one coming from FFmpeg that is used as a fallback. If you experience any bad behaviour with mp3 files (skipping, distorted sound) make sure you enabled this USE flag.
mmap Use mmap() function while reading file from local disks. Using mmap() will use more virtual memory space, but leaves to the Kernel the task of caching the file's data. mmap() access should be faster, but might misbehave if the device where the file resides in is removed during playback.
truetype Use media-libs/freetype for font rendering and media-libs/fontconfig for font discovery. Enabling this USE flag will allow OSD (such as subtitles) to use more advanced font and to more easily select which font to use. The support for TrueType fonts in xine-lib is still experimental, and might not be as good looking as the bitmap fonts used with this USE flag disabled.
vdr Build the VDR plugin
vidix Enable support for vidix video output.
vis Adds support for SIMD optimizations for UltraSPARC processors.
vpx Enable VP8 codec support via media-libs/libvpx.
xvmc Enable support for XVideo Motion Compensation (accelerated mpeg playback).

xvid

pic disable optimized assembly code that is not PIC friendly

media-plugins

alsa-plugins

arcam_av Enables Arcam AV control plugin
mix Enables upmix and vdownmix plugin
usb_stream Enables usb_stream plugin

audacious-plugins

adplug Build with AdPlug (Adlib sound card emulation) support
ampache Support controlling audacious via www-apps/ampache
aosd Enable support for Audacious OSD
bs2b Enable Bauer Bauer stereophonic-to-binaural headphone filter
cue Support CUE sheets using the libcue library
fluidsynth Support FluidSynth as MIDI synth backend
gme Support various gaming console music formats
gtk3 Link against version 3 of the GIMP Toolkit instead of version 2 (x11-libs/gtk+)
hotkeys Enable support for controlling via hotkeys
http Support HTTP streams through neon
scrobbler Build with scrobbler/LastFM submission support
sid Build with SID (Commodore 64 Audio) support
soxr Build with SoX Resampler support
speedpitch Enable speed/pitch effects

calf

experimental Enable experimental features/plugins
lv2 Add support for Ladspa V2

frei0r-plugins

facedetect Enables building of facedetect plugin, which depends on media-libs/opencv
scale0tilt Enables building of scale0tilt and vectorscope plugins, which depend on media-libs/gavl

gkrellmpc

threads Use separate thread to init connection (unsafe)

grilo-plugins

chromaprint Enable Chromaprint support
daap Enable dmap support through net-libs/libdmapsharing
flickr Enable Flickr support
freebox Build support for viewing TV channels using Freebox
gnome-online-accounts Enable net-libs/gnome-online-accounts support
subtitles Enables support for subtitle from OpenSubtitles
thetvdb Build support for thetvdb.com
tracker Build support for content discovery using the app-misc/tracker indexer
vimeo Build support for Vimeo content discovery using net-libs/libsoup and dev-libs/libgcrypt
youtube Build support for YouTube content discovery using dev-libs/libgdata

gst-plugins-gl

libvisual Enable visualization effects via media-libs/libvisual

gst-plugins-gtk

egl Enable EGL platform usage
gles2 Enable gtkglsink OpenGL sink based on GLESv2 API
opengl Enable gtkglsink OpenGL sink based on desktop OpenGL API

gst-plugins-meta

http Enable http streaming via net-libs/libsoup
libvisual Enable visualization effects via media-libs/libvisual
vpx Enables vp8 codec support using libvpx, required to play some HTML5 videos

gst-plugins-vaapi

drm Enable DRM renderer
egl Enable EGL support
gles2 Enable GLESv2 and GLESv3 support

hexter

gtk2 Enable x11-libs/gtk+:2 based GUI

imlib2_loaders

eet Enable Eet image loader
xcf Enable XCF image loader

kipi-plugins

flashexport Build the flash export plugin
mediawiki Build the mediawiki export plugin
remotestorage Build plugin for remote storage using network protocols such as FTP, SSH, SAMBA via kde-frameworks/kio
vkontakte Build plugin for vkontakte.ru

mediastreamer-ilbc

20ms-frames enable 20ms frame size (default is 30ms). Some VOIP providers such as Gizmo5 (aka Sipphone) require the codec to be compiled with the 30ms setting.

mythplugins

cdr Allows MythMusic to burn CD-Rs
exif Allows MythGallery to read EXIF data from photos
fftw Adds visual effects to MythMusic when playing back music
hls HTTP Live Streaming support
mytharchive Allows you to archive recorded content to CD or DVD
mythbrowser Adds a web browser within MythTV
mythgallery Adds a picture viewing gallery within MythTV
mythgame Adds a frontend to various ROM emulators within MythTV
mythmusic Adds the ability for MythTV to act as a music player
mythnetvision Adds the ability to view netvision devices within MythTV
mythnews Adds a news viewer within MythTV
mythweather Adds weather information within MythTV
mythzoneminder Adds support for zoneminder (requires a server with the appropriate mythtv daemon somewhere on the network).
raw Allows MythGallery to view photos saved in RAW format

vdr-burn

dvdarchive DMH DVD - Archive

vdr-dvbapi

dvbcsa use media-libs/libdvbcsa free implementation of the DVB Common Scrambling Algorithm

vdr-epgsearch

conflictcheckonly install the "conflictcheckonly" vdr-plugin
epgsearchonly install the "epgsearchonly" vdr-plugin
quicksearch install the "quicksearch" vdr-plugin
tre Add support for unlimited fuzzy searching with help of dev-libs/tre library

vdr-pvr350

yaepg Enables full support for the output format of vdr-yaepg

vdr-streamdev

client Compile the VDR plugin vdr-streamdev-client that acts like a dvb-budget card
server Compile the VDR plugin vdr-streamdev-server that allows remote systems to access the DVB cards used for the local VDR

vdr-vdrmanager

stream Add support for streaming Video to Android client

vdr-weatherng

dxr3 enables lower osd color depth for dxr3 cards

vdr-xineliboutput

bluray Enable BluRay metadata support through media-libs/libbluray
cec Enable CEC support through dev-libs/libcec
libextractor Use media-libs/libextractor to gather files' metadata in media-player
vdr Compile the vdr output plugin to use local or remote xine as output
xine Compile the xine input plugin for displaying vdr video and OSD

media-radio

ax25-tools

X Enable some X based configuration tools.

fldigi

hamlib Enables support by the Hamlib amateur radio rig control library to get/set frequency and mode of the ham radio in use

tucnak

hamlib Enables support by the Hamlib amateur radio rig control library to get/set frequency and mode of the ham radio

unixcw

ncurses Enables building the curses based morse code tutor program 'cwcp'.

xastir

festival Enable text to speech synthesizer
gdal Support for some further map formats
geotiff Install geotiff support. Allows using USGS DRG topo maps or other types of geotiff mapes/images

media-sound

abcde

id3tag Support ID3, ID3v2 tagging of audio files
mac Enable support for Monkey's Audio files
normalize Add support for normalizing audio file volume levels
replaygain Support for Replay Gain metadata, for relative volume adjustment

abcm2ps

pango Use the pango library to render fonts with non-latin characters

alsa-utils

bat install basic audio tester (BAT) util
libsamplerate install utils that use libsamplerate (e.g. alsaloop)
ncurses install utils that use ncurses (e.g. alsamixer)

alsaplayer

id3tag Enables ID3 tagging with id3tag library

amsynth

dssi Enable support for DSSI Soft Synth Interface

apulse

sdk Install PulseAudio headers and pkg-config files. Be aware apulse is not a full PulseAudio replacement by design and some functionality may be missing.

aqualung

ifp Enable support for iRiver iFP portable audio players
lua Enable support for programmable title formatting with dev-lang/lua
mac Enable support for decoding Monkey's Audio files
podcast Enable podcast support
systray Enable system tray support

ario

audioscrobbler Enable song tracking via last.fm
idle Enable experimental support for MPD's idle command to reduce bandwidth and cpu usage, requires MPD 0.14

asunder

mac Support for creation of Monkey's Audio files (APE)

audacious

gtk3 Link against version 3 of the GIMP Toolkit instead of version 2 (x11-libs/gtk+)

audacity

id3tag Enables ID3 tagging with id3tag library
lv2 Add support for Ladspa V2
midi Enables MIDI support
portmixer Enable the internal portmixer feature
sbsms Enables sbsms library support for slower, more accurate pitch and tempo changing
soundtouch Enables soundtouch library support for pitch and tempo changing
twolame Enables twolame support (MPEG Audio Layer 2 encoder)
vamp Enables vamp plugins support (Audio analysing plugins)
vst Enable VST plugin support

beets

badfiles Validate MP3 & FLAC files
chromaprint Enable support for acoustic fingerprinting plugin using media-libs/chromaprint
discogs Enable support for the discogs API plugin
ffmpeg Enable support for the convert plugin to transcode files via media-video/ffmpeg
lastfm Enable support for importing personal last.fm playcounts and music genres from last.fm tags
mpd Enable support for media-sound/mpd server emulation and statistic gathered from media-sound/mpd
replaygain Enable support for Replay Gain metadata calculation during import
thumbnail Enable album thumbnails generation
webserver Enable embedded webse