Merge remote-tracking branch 'remotes/kraxel/tags/pull-audio-20151215-1' into staging

coreaudio: use new-in-OSX-10.6 APIs, cleanups.

# gpg: Signature made Tue 15 Dec 2015 10:15:24 GMT using RSA key ID D3E87138
# gpg: Good signature from "Gerd Hoffmann (work) <kraxel@redhat.com>"
# gpg:                 aka "Gerd Hoffmann <gerd@kraxel.org>"
# gpg:                 aka "Gerd Hoffmann (private) <kraxel@gmail.com>"

* remotes/kraxel/tags/pull-audio-20151215-1:
  audio/coreaudio.c: Avoid deprecated AudioDeviceAdd/RemoveIOProc APIs
  audio/coreaudio.c: Use new-in-OSX-10.6 APIs when available
  audio/coreaudio.c: Factor out uses of AudioDeviceGet/SetProperty
  audio/coreaudio.c: Use new-in-OSX-10.6 API for getting default voice
  audio/coreaudio.c: Factor out use of AudioHardwareGetProperty

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>