Now the operation state change we're waiting on will signal the
threaded mainloop, so this doesn't wait longer than necessary.
This requires PulseAudio 4.0 or later, so don't merge this into SDL2,
which requires PulseAudio 0.9.15.
Fixes#7971.
Simple DirectMedia Layer is a cross-platform development library designed
to provide low level access to audio, keyboard, mouse, joystick, and graphics
hardware via OpenGL and Direct3D. It is used by video playback software,
emulators, and popular games including Valve's award winning catalog
and many Humble Bundle games.
More extensive documentation is available in the docs directory, starting
with README.md