Miniaudio

- Fix some subtle multi-threading bugs on non-x86 platforms.
- Fix a bug resulting in superfluous memory allocations when enumerating devices.
- Core Audio: Fix a compilation error when compiling for iOS.

- Fix a crash when initializing a POSIX thread.
- OpenSL|ES: Respect the MA_NO_RUNTIME_LINKING option.

- Add support for dynamically configuring some properties of `ma_noise` objects post-initialization.
- Add support for configuring the channel mixing mode in the device config.
- Fix a bug with simple channel mixing mode (drop or silence excess channels).
- Fix some bugs with trying to access uninitialized variables.
- Fix some errors with stopping devices for synchronous backends where the backend's stop callback would get fired twice.
- Fix a bug in the decoder due to using an uninitialized variable.
- Fix some data race errors.

- WASAPI: Fix a bug where the exclusive mode format may not be retrieved correctly due to accessing freed memory.
- Fix a bug with ma_waveform where glitching occurs after changing frequency.
- Fix compilation with OpenWatcom.
- Fix compilation with TCC.
- Fix compilation with Digital Mars.
- Fix compilation warnings.
- Remove bitfields from public structures to aid in binding maintenance.

- PulseAudio: Fix a bug where the stop callback isn't fired.
- WebAudio: Fix an error that occurs when Emscripten increases the size of it's heap.
- Custom Backends: Change the onContextInit and onDeviceInit callbacks to take a parameter which is a pointer to the config that was
passed into ma_context_init() and ma_device_init(). This replaces the deviceType parameter of onDeviceInit.
- Fix compilation warnings on older versions of GCC.

- Fix a bug where initialization of a backend can fail due to some bad state being set from a prior failed attempt at initializing a
lower priority backend.