sunos_ioctl.c failed to compile recently because of the revamp work that
has been going on the audio subsystem.

The SunOS audio subsystem has the ability to query and set the ''monitor
gain'' of an audio device.  It appears that the compat code intended to
one day communicate the status of the monitor gain through a member of the
NetBSD audio_info struct named ``__spare'', but it doesn't appear that it
ever made use of it.

This structure member was recently removed, thus causing an undefined
member reference during compilation.  The code has been changed to return
a monitor gain value of zero when queried, and ignore the value when set. 
I don't think this breaks any existing behavior that wasn't already
broken, but this is a heads-up just in case. 

-J