As child windows can be recursively destroyed when their parents are destroyed, emit an event to notify the application when a window is being or has been implicitly destroyed so that it can appropriately clean up any associated resources.
If the application has registered an event watch, the destroy message will be received when the window handle is still valid, so the application can retrieve and release any userdata associated with the window. If the message is processed at any time after that, the window handle is already invalid and the ID is only useful for application-side bookkeeping purposes.
`SDL_QUERY`, `SDL_IGNORE`, `SDL_ENABLE`, and `SDL_DISABLE` have been removed.
SDL_EventState() has been replaced with SDL_SetEventEnabled()
SDL_GetEventState() has been replaced with SDL_EventEnabled()
SDL_GameControllerEventState has been replaced with SDL_SetGamepadEventsEnabled() and SDL_GamepadEventsEnabled()
SDL_JoystickEventState has been replaced with SDL_SetJoystickEventsEnabled() and SDL_JoystickEventsEnabled()
SDL_ShowCursor() has been split into three functions: SDL_ShowCursor(), SDL_HideCursor(), and SDL_CursorVisible()
Fixes https://github.com/libsdl-org/SDL/issues/6929
Instead of indexing into an internal list of devices which requires locking, we return a list of device IDs which can then be queried individually.
Reference: https://github.com/libsdl-org/SDL/issues/6889
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