This only allows the alsa-lib query to come up, which technically only
disables alsa if 'n', otherwise it uses alsa if it's on the system. In
BUILD alsa is forcefully removed, so even now ALSA will not be used.
$ gaze BUILD soundtracker
OPTS="$OPTS --disable-alsa"
default_build
Did you test ALSA support just by uncommenting? If so, then ALSA was
still disabled.