handle lack of locators in LKM context differently.
don't require that the aed unit number be zero.
only match one instance (instead of an unlimited number).
simplify by not pretending that mac68k can have more than 1 zsc.
simplify by not pretending that mac68k can have more than 1 zsc.
Apply patch hpcmips/26158 (requested by darkstar)
This patch solves install/28656.
add AUDIO_KMIXER option.
  AUDIO_KMIXER is not defined or AUDIO_KMIXER is 1:
	a /dev/audioN can be opened just once.
  AUDIO_KMIXER is <= 0:
	a /dev/audioN can be opened unlimitedly.
  AUDIO_KMIXER is > 0 and <= INT_MAX:
	a /dev/audioN can be opened AUDIO_KMIXER times simultaneously.
add entiries for cloned fd
sync with -current
* add AUDIO_PROP_PLAY and AUDIO_PROP_RECORD for internal use
  XXX: need to modify all of audio HW drivers.

* At the first open(), open the HW as play and record mode even if the open
flags contains either FREAD or FWRITE.

* remove AUMODE_READ and AUMODE_WRITE, and use FREAD and FWRITE instead.
add PCM mixing filter
simplify logical operations
sync with -current