Add support for extra TeXLive packages

Packages describing “extra” as local USE flag

Package “extra” Flag Description
app-text/texlive Add support for extra TeXLive packages
dev-php/pecl-event Add support of the Libevent extra API
dev-python/nltk-data Install the complete set of data files. Otherwise, only files required by tests are installed.
media-fonts/noto Install full upstream font set
media-video/pipewire Build pw-cat/pw-play/pw-record
app-shells/nushell Install extra plugins: binaryview, tree, clipboard-cli, trash-support and others
app-i18n/rime-data Install extra packages
sys-block/f3 Build the additional f3probe, f3brew and f3fix utility (requires sys-block/parted and virtual/udev)

All packages providing a “extra” USE flag (5)