Correct, OSS should work out-of-the-box on Solaris 11 and up since it is
the default audio system there.  OSS was also integrated into OpenSolaris, so it is probably the most sensible audio plugin to use there also.  Some end-users may build and install their own OSS code on Solaris 10 or earlier, so it should not hurt to try and build the OSS plugin even on older versions of Solaris. 

Also, I'm not sure if the way I'm doing the #ifndef's in the patch is right.  Looking at the rest of the code, I see that each EXPORT_INT is
surrounded by its own #ifdef.  I added similar #ifdef's around SNDCTL_DSP_BIND_CHANNEL SNDCTL_DSP_MAPINBUF, and SNDCTL_DSP_MAPOUTBUF.
However I just put "#ifndef __sun" around the SNDCTL_COPR_* and
SNDCTL_DSP_* ioctls because it seemed to make the patch more simple.
But, I'm not sure this was the right decision.  Maybe it just might be
more consistent to use an #ifdef around each one separately.