wasapi: ensure that wasapi context structure is zeroed before filling it

I had a situation where I was doing:

    ma_backend backends[] = {
	ma_backend_jack,
	ma_backend_wasapi,
    };
    ma_context_init(backends, sizeof(backends)/sizeof(backends[0]),
	&contextConfig, &context);

And since JACK was unavailable, it fell back to WASAPI. When this
happened, the WASAPI commandIndex and commandCount variables were
already stomped on by the JACK backend initialization, but the WASAPI
backend assumes they are zero-initialized.
Signed-off-by: Steven Noonan <steven@uplinklabs.net>

Fix linker error when MA_NO_RESOURCE_MANAGER is defined

Fix -Wcast-qual by using correct ma_offset_pcm_frames_ptr()

Fix CoreAudio's performanceProfile for playback not being set

Fix memory leak (macOS)

engine: use atomics for setting live pitch and spatialization variables

Signed-off-by: Steven Noonan <steven@uplinklabs.net>

Thread Sanitizer was unhappy about these variables being modified on one
thread and read on another (data race).
Signed-off-by: Steven Noonan <steven@uplinklabs.net>

Signed-off-by: Steven Noonan <steven@uplinklabs.net>

Signed-off-by: Steven Noonan <steven@uplinklabs.net>

fix iOS deadlocks