SDL_GetClipboardMimeTypes() does not work

[ronaaron]

At least on Linux, even though I get e.g. "text/html" from the clipboard with SDL_GetClipboardData(), nothing is returned from:

	size_t size = 0;
	char ** mimes = SDL_GetClipboardMimeTypes(&size);

mimes points to data, but there's no data there and size remains 0.

[ronaaron]

I see that it only works if I first place data on the clipboard in my app; it doesn't seem to be aware of the system clipboard's current state otherwise.