Added SDL_GetWindowFromEvent

[madebr]

Add SDL_GetWindowIDFromEvent SDL_GetWindowFromEvent as a convenience function to get the window id from a SDL_event.

To fix the imgui event handling without modifying imgui's code, you can do:

extern SDL_Window *imgui_sdl_window;
SDL_Event event;
SDL_Window *event_window = SDL_GetWindowFromEvent(&event);
if (event_window == imgui_sdl_window || event_window == NULL) {
    ImGui_ImplSDL3_ProcessEvent(&event);
}

@slouken
The xcode project needs an update: I added the new code to src/events/SDL_categories.c and src/events/SDL_categories_c.h
CI does not build any xcode test projects, so this issue is not caught.

Description

Existing Issue(s)

Fixes #10457

[slouken]

Can you change it to SDL_GetWindowFromEvent()?

Also, can we add an Xcode build to CI, or is that crazy talk? :)

[madebr]

Also, can we add an Xcode build to CI, or is that crazy talk? :)

Xcode is built, see the tvOS (xcode) and iOS (xcode) jobs.
I'm just saying the xcode projects only build SDL3 and SDL3_test, no tests.
So a missing symbol is not catched.

[slouken]

Also, can we add an Xcode build to CI, or is that crazy talk? :)

Xcode is built, see the tvOS (xcode) and iOS (xcode) jobs. I'm just saying the xcode projects only build SDL3 and SDL3_test, no tests. So a missing symbol is not catched.

Oh, gotcha.

[madebr]

Can you change it to SDL_GetWindowFromEvent()?

It still returns a SDL_WindowID? Or should it pull the window id through SDL_GetWindowFromID?

[slouken]

Can you change it to SDL_GetWindowFromEvent()?

It still returns a SDL_WindowID? Or should it pull the window id through SDL_GetWindowFromID?

It should return SDL_Window *

[slouken]

Suggested change

	* Get the associated window of an event.
	* Get window associated with an event.

[slouken]

Suggested change

	* \param event SDL event of which to get the window.
	* \param event an event containing a `windowID`

[madebr]

I added these to document the 2 cases.

[madebr]

(Don't forget about the xcode project)