SDL 2.x recently accepted patches to enable OpenGL ES 2 support via Google's ANGLE library. The thought is to try to eventually merge SDL/WinRT's OpenGL code with SDL-official's.
XAudio2 2.8's header file, xaudio2.h, doesn't compile in plain C code for WinRT
apps, not automatically at least. Initially, this file was adapted to compile
as C++, however these changes are now deprecated in favor of some preprocessor
based hacks that should get xaudio2.h to compile (while making sure XAudio2
still works).
If the app is in landscape mode and the user presses the power button, a pause
is followed immediately by a surfaceChanged event because the lock screen
is shown in portrait mode. This triggers a "false" resume.
So, we just pause and resume following the onWindowFocusChanged events.
Also, wait for SDL_APP_WILLENTERBACKGROUND and SDL_APP_DIDENTERBACKGROUND before
blocking the event pump.
