I had both games-fps/doomsday-2.0.3 and media-libs/sdl2-mixer-2.0.1 installed. After removing sdl2-mixer I got: >>> package: media-libs/sdl2-mixer-2.0.1 * - /usr/lib64/libSDL2_mixer-2.0.so.0 * - /usr/lib64/libSDL2_mixer-2.0.so.0.0.1 * used by /usr/bin/doomsday-2.0.3 (games-fps/doomsday-2.0.3) Doomsday builds fine without sdl2-mixer.
Still true in 2.1.1 but I'll fix this another time.
Just noticed that fluidsynth, fmod, and openal are probably automagic too.