The repro steps were this:
1. run an sdl2 winrt/uwp app, on Win10, v10.0.10586.0 or higher
2. hide the cursor, via a call to SDL_ShowCursor(0)
3. make the Win10 game bar appear, by pressing the Windows + G hotkey
4. observe that the mouse cursor appears, in order to interact with the
game bar (this is expected behavior)
5. make the Win10 game bar disappear, either by pressing the Windows + G hotkey
again, or clicking somewhere in the app
EXPECTED RESULT: cursor disappears, as game bar disappears
ACTUAL RESULT: cursor didn't always disappear
The internal function SDL_EGL_LoadLibrary() did not delete and remove a mostly
uninitialized data structure if loading the library first failed. A later try to
use EGL then skipped initialization and assumed it was previously successful
because the data structure now already existed. This led to at least one crash
in the internal function SDL_EGL_ChooseConfig() because a NULL pointer was
dereferenced to make a call to eglBindAPI().
