Aaron Barany
Since OpenGL is deprecated on iOS, it is advantageous to be able to remove all OpenGL related code when building SDL for iOS. This patch adds the necessary #if checks to compile in this case.
The Apple TV remote is currently exposed as a joystick with its touch surface treated as two axes. Key presses are also generated when its buttons and touch surface are used.
A new hint has been added to help deal with deciding whether to background the app when the remote's menu button is pressed: SDL_HINT_APPLE_TV_CONTROLLER_UI_EVENTS.
Note that extra steps must be taken when using glReadPixels to read the contents of the main OpenGL ES framebuffer on iOS, if multisampling is used. See the OpenGL ES section of README-ios.md for details.
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().
