The previous method wasn't good enough: we were still maxing-out at
96 (did the Decaf devs misread that as hex? Is that why the
emulator's limit is 150 instead?).
Anyway, this new solution is a little brutish, but I can't think of
anything else that would work: right now, I have the Organya thread
constantly polling a linked-list of the currently-loaded sounds, and
checking if their voices have finished playing or not. If they've
finished, they get freed.
When AudioBackend_PlaySound is called, if checks if the sound's voice
has been freed or not, and reallocates it if it has.
There doesn't seem to be a noticable overhead to this, and it keeps
the number of currently-allocated voices *very* low (from 10 to 20 on
average).
I'm getting some rare audio hangs. I tried doing some
regression-testing, but it's so random that I'm getting anomalous
results. That said, there were suspicious results around this change
(and also the way `mix_data` is initialised/cleared), so I'm
reverting this for now, and restoring it next time I encounter a
hang.
Currently doesn't produce sound unless you stop Organya from calling
AudioBackend_CreateSound, because it exhausts the Wii U's 150-sound
pool before the SFX get any of them.
