Feature request: Have the clipboard update events say which clipboard changed

[rakslice]

Right now SDL 2 and SDL 3 have separate sets of API calls for two clipboard-like things in X11 and similar, the Clipboard and the Primary Selection, and the SDL_CLIPBOARDUPDATE (SDL 2) / SDL_EVENT_CLIPBOARD_UPDATE (SDL 3) event correctly fires for either of them changing.

However it doesn't indicate which of them changed.

In practice this means the best an application can do if it needs to know when a user copied something to a particular one, for time sequencing reasons, is to bolt on some logic after the event to keep track of which contents changed and try to deduce what the event was, and even then that will never be 100% because it can't disambiguate the case when a copy happened of the same thing that was already in the clipboard.