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.
SDL_syssem.c:159 comparison of unsigned expression >= 0 is always true
Solved by comparing unsigneds directly
SDL_systimer.c:164: warning: control may reach end of Compile
Solved by returning the default value if all else fails.
SDL_androidgl.c:41:1: warning: type specifier missing, defaults to 'int'
SDL_androidgl.c:47:1: warning: control reaches end of non-void function
Solved by adding void return type to the function implementation
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.
