This fixes behavior with the new Mac OS X fullscreen space code, as well as improve behavior on Linux desktops.
The default for normal fullscreen mode is still to minimize because we're likely doing a mode switch and don't want to stick around as a borderless window in the background.
Andreas Ertelt
The problem in question is caused by changeset 7771 (http://hg.libsdl.org/SDL/rev/5486e579872e / https://bugzilla.libsdl.org/show_bug.cgi?id=2121)
The redefinition of __inline__ (introduced by the addition of begin_code.h:128's "|| __STRICT_ANSI__") results in mingw's gcc throwing multiple
warning: always_inline function might not be inlinable [-Wattributes]
as well as a whole bunch of redefinitions of mingw internals which break linking of projects including the SDL2 headers.
This reverts http://hg.libsdl.org/SDL/rev/7cdeb64faa72 and fixes it in
the correct way. If you call SDL_SetWindowPosition on a fullscreen
window, it would update the x & y variables for the window, but not
actually move the window (since it was fullscreen). That would make the
internal state of the SDL_Window incorrect, causing
SDL_WarpMouseInWindow to offset incorrectly.
This makes it so SDL_SetWindowPosition updates the `windowed' x & y
coordinates, which take effect when you revert from fullscreen.
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.
