* Remove depth field from SDL_CreateRGBSurfaceWithFormat and SDL_CreateRGBSurfaceWithFormatFrom
* Removed unused 'flags' parameter from SDL_CreateRGBSurface and SDL_CreateRGBSurfaceWithFormat
* Removed unused 'flags' parameter from SDL_ConvertSurface and SDL_ConvertSurfaceFormat
I ran this script in the include directory:
```sh
sed -i '' -e 's,#include "\(SDL.*\)",#include <SDL3/\1>,' *.h
```
I ran this script in the src directory:
```sh
for i in ../include/SDL3/SDL*.h
do hdr=$(basename $i)
if [ x"$(echo $hdr | egrep 'SDL_main|SDL_name|SDL_test|SDL_syswm|SDL_opengl|SDL_egl|SDL_vulkan')" != x ]; then
find . -type f -exec sed -i '' -e 's,#include "\('$hdr'\)",#include <SDL3/\1>,' {} \;
else
find . -type f -exec sed -i '' -e '/#include "'$hdr'"/d' {} \;
fi
done
```
Fixes https://github.com/libsdl-org/SDL/issues/6575
SDL_HINT_VIDEO_X11_FORCE_EGL was deprecated in favor of the more general SDL_HINT_VIDEO_FORCE_EGL, and Xinerama and Xvidmode support was previously removed from SDL, rendering their associated hints nonfunctional.
* 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
