We want to move the AO to its own thread. There's no technical reason
for making the ao struct opaque to do this. But it helps us sleep at
night, because we can control access to shared state better.
Reverts one of the changes from 18777ecf. `kAudioObjectPropertyScopeOutput`
was introduced in the 10.8 SDK while `kAudioDevicePropertyScopeOutput` was
moved to `AudioHardwareDeprecated.h`. Since the deprecation is silent for now
(no warnings), just use the old constant.
Either way, they both evaluate to 'outp', and in the 10.8 SDK the deprecated
constant is defined in terms of the non-deprecated one.
Fixes#155
Introduce some macros to deal with properties. These allow to work around the
limitation of CoreAudio's API being `void **` based. The macros allow to keep
their client's code DRY, by not asking size and other details which can be
derived by the macro itself. I have no idea why Apple didn't design their API
like this in the first place.
* ao_coreaudio_utils: contains several utility function
* ao_coreaudio_properties: contains functions to set and get audio object
properties.
Conflicts:
audio/out/ao_coreaudio.c
