depends cmake &&
optional_depends alsa-lib   ""  "" "ALSA backend"   &&
optional_depends LIBAVCODEC ""  "" "FFMpeg backend" &&
optional_depends jack2      ""  "" "JACK backend" &&
optional_depends sdl2       ""  "" "SDL2 backend" &&
optional_depends portaudio19 "-DPORTAUDIO=ON" "-DPORTAUDIO=OFF" \
                             "for a portaudio backend" &&
optional_depends pulseaudio "-DPULSEAUDIO=ON" "-DPULSEAUDIO=OFF" \
                            "for a pulseaudio backend"