alsa - Add support for media-libs/alsa-lib (Advanced Linux Sound Architecture)
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
jack - Add support for the JACK Audio Connection Kit
mad - Add support for mad (high-quality mp3 decoder library and cli frontend)
pulseaudio - Add sound server support via media-libs/libpulse (may be PulseAudio or PipeWire)
