[freespace2] freespace2 OSX audio problems

[Jonas Laurio]

Commenting out the 'offending' lines in audiostr.cpp does not help, 
(more show up after the initial ones are removed). After I do that, 
then all sorts of openal error check lines in src/sound/ds.cpp fly off 
about the data they get (because they don't get it since those lines 
are gone in the other >?).

Anyhow the ones I noticed that initially complained starting the 
problem are the ones using the m_al_multichannel_id. Can you test it on 
a NON_multichannel setup over there, or does this even matter? If 
openal returns multichannel is not available could this be causing the 
issue, or am I just overthinking this...

-d