This makes the subsystem thread-safe, more performant, and cleans up the code a little.
Also removed SDL_HINT_WINDOWS_FORCE_MUTEX_CRITICAL_SECTIONS, since setting this hint programmatically initializes properties, which creates a lock, so we can't check hints while creating locks. The slim reader-writer locks have been the default for ages and are solid, so we'll just use those when available.
Removed duplicate hints SDL_HINT_APP_NAME, SDL_HINT_APP_ID, and
SDL_HINT_AUDIO_DEVICE_APP_NAME.
Wired up a few things to use the metadata; more to come!
Fixes https://github.com/libsdl-org/SDL/issues/4703
It was intended to make the API easier to use, but various automatic garbage collection all had flaws, and making the application periodically clean up temporary memory added cognitive load to using the API, and in many cases was it was difficult to restructure threaded code to handle this.
So, we're largely going back to the original system, where the API returns allocated results and you free them.
In addition, to solve the problems we originally wanted temporary memory for:
* Short strings with a finite count, like device names, get stored in a per-thread string pool.
* Events continue to use temporary memory internally, which is cleaned up on the next event processing cycle.
Move the Wayland pointer warp emulation code up to the SDL mouse layer, and activate it when a client attempts to warp a hidden mouse cursor when the hint is set.
testrelative adds the ability to test the warp emulation activation/deactivation with the --warp parameter and 'c' key for toggling cursor visibility.
This change also decouples the pause/resume handling from the video subsystem on Android, so applications that don't use SDL for video can get application life cycle events.
The semantics for the life cycle events are that they need to be handled in an event watch callback, and once they've been delivered, the application will block until it's been resumed. SDL_HINT_ANDROID_BLOCK_ON_PAUSE can be used to control that behavior, and if that's set to "0", then the application will continue to run in the background at low CPU usage until being resumed or stopped.
SDL_HINT_ANDROID_BLOCK_ON_PAUSE_PAUSEAUDIO has been removed, and the audio will be paused when the application is paused.
Fixes https://github.com/libsdl-org/SDL/issues/3193
