in kvm-70 was possible to enable support to the fmon audio driver ( media-libs/fmod) by using --enable-fmod, for kvm-71 it will require instead adding "fmod" to the list of available --audio-drv-list ($audio_opts)
What does fmod gain you that alsa, oss, esd, pulseaudio, and sdl do not? I have no problem with it in principle, but proliferation of options in and of itself isn't necessarily a good thing.
Get back to us.