[CM] moving cursor

[Bill Schottstaedt]

 > when i load any soundfile after loading snd_conffile.scm it seem to
 > play at twice the speed or more

This is caused by complete stupidity in my Mac/OSX audio code, but it's
too hard to fix, so I've limited the dac-size in that case to 256 or
less.  (The bug is tickled by the line (set! (dac-size) 2048)).

As audio hardware has changed over the years, audio.c has slowly
become detached from reality; its model of what's out there no
longer fits what is actually out there.  But a fix is a huge job,
and 5 years down the road it will probably need to be done all
over again.  Job security?