Fixes#135897 by introducing a mixing thread to coreaudio, making the callback lock free. At the same time these changes unify all devices that use a mixing thread (now that's jack, pulse, pipewire and coreaudio).
Pull Request: https://projects.blender.org/blender/blender/pulls/136711
Removes the playback handle from the synchronizer API and integrates it
into the device, removing the ISynchronizer interface completely.
This has been discussed in more detail in #126047 and its main purpose is to unify the handling of synchronizer events, especially seek which needed different logic for jack vs other backends.
OpenAL now needs a silence playback handle for synchronization but all
other backends are pretty straightforward just counting the mixed
samples in the SoftwareDevice with some specializations for specific
backends that had their own synchronizers before.
Note: CoreAudio changes are untested as I don't have a Mac.
Pull Request: https://projects.blender.org/blender/blender/pulls/133191
Turns out closing AudioUnit handle could interfere with other software.
It is something Apple is investigating, to see if it is API not used
correctly, or whether there is something to be fixed in the Core Audio.
Until then disable the code which closes audio handles. It rolls back
to the situation when the computer might not be able to sleep properly,
but it is how the previous release was, and overall it is less annoying
than causing an interference.
Once the issue is looked into by Apple we will re-iterate over having
both issues (interference and power management) resolved.
Pull Request: https://projects.blender.org/blender/blender/pulls/124400
