clipboard: add SDL_ClipboardMimeTypes

This function allows to retrieve the available mime types without doing any
synthesizing.

include/SDL3/SDL_clipboard.h

@@ -42,6 +42,20 @@ extern "C" {
 
 /* Function prototypes */
 
+/**
+ *  Retrieve the list of mime types available in the clipboard.
+ *
+ * \param num_mime_types a pointer filled with the number of mime types. May be NULL.
+ * \returns a null terminated array of strings with mime types, or NULL on
+ *          failure; call SDL_GetError() for more information. This should be
+ *          freed with SDL_free() when it is no longer needed.
+ *
+ * \since This function is available since SDL 3.0.0.
+ *
+ * \sa SDL_SetClipboardData
+ */
+extern SDL_DECLSPEC char ** SDLCALL SDL_GetClipboardMimeTypes(size_t *num_mime_types);
+
 /**
  * Put UTF-8 text into the clipboard.
  *