optional_depends alsa-lib \
                 --{with,without}-alsa \
                 "for ALSA support" &&
optional_depends pulseaudio \
                 --{with,without}-pulseaudio \
                 "for PulseAudio support" &&
optional_depends libsndfile \
                 --{with,without}-sndfile \
                 "for sndfile support" &&
depends fftw
