* The header is no longer dependent on SDL build configuration
* The structures are versioned separately from the rest of SDL
* SDL_GetWindowWMInfo() now returns a standard result code and is passed the version expected by the application
* Updated WhatsNew.txt and docs/README-migration.md with the first API changes in SDL 3.0
Most of these are probably harmless, but the changes to SDL_immdevice.c and SDL_pixels.c appear to have fixed genuine bugs.
SDL_audiocvt.c: By separating the calculation of the divisor, I got rid of the suspicion that dividing a double by an integer led to loss of precision.
SDL_immdevice.c: Added a missing test, one that could have otherwise led to dereferencing a null pointer.
SDL_events.c, SDL_gamecontroller.c, SDL_joystick.c, SDL_malloc.c, SDL_video.c: Made it clear the return values weren't used.
SDL_hidapi_shield.c: The size is zero, so nothing bad would have happened, but the SDL_memset() was still being given an address outside of the array's range.
SDL_dinputjoystick.c: Initialize local data, just in case IDirectInputDevice8_GetProperty() isn't guaranteed to write to it.
SDL_render_sw.c: drawstate.viewport could be null (as seen on line 691).
SDL.c: SDL_MostSignificantBitIndex32() could return -1, though I don't know if you want to cope with that (what I did) or SDL_assert() that it can't happen.
SDL_hints.c: Replaced boolean tests on pointer values with comparisons to NULL.
SDL_pixels.c: Looks like the switch is genuinely missing a break!
SDL_rect_impl.h: The MacOS static checker pointed out issues with the X comparisons that were handled by assertions; I added assertions for the Y comparisons.
SDL_yuv.c, SDL_windowskeyboard.c, SDL_windowswindow.c: Checked error-result returns.
It turns out that we can safely create a Metal view on an existing window, and that avoids issues with the window being recreated with the wrong orientation in iOS 16.
Fixes https://github.com/libsdl-org/SDL/issues/6289
This kicks in if the platform doesn't support vsync directly, or if the present fails for some reason (e.g. minimized on some platforms)
Fixes https://github.com/libsdl-org/SDL/issues/5134
