Add SDL_HINT_MOUSE_RELATIVE_CLIP_INTERVAL (#10085)

include/SDL3/SDL_hints.h

@@ -2337,6 +2337,19 @@ extern "C" {
  */
 #define SDL_HINT_MOUSE_RELATIVE_CURSOR_VISIBLE  "SDL_MOUSE_RELATIVE_CURSOR_VISIBLE"
 
+/**
+ * Controls how often SDL issues cursor confinement commands to the operating
+ * system while relative mode is active, in case the desired confinement state 
+ * became out-of-sync due to interference from other running programs.
+ *
+ * The variable can be integers representing miliseconds between each refresh.
+ * A value of zero means SDL will not automatically refresh the confinement.
+ * The default value varies depending on the operating system, this variable
+ * might not have any effects on inapplicable platforms such as those without
+ * a cursor.
+ */
+#define SDL_HINT_MOUSE_RELATIVE_CLIP_INTERVAL  "SDL_MOUSE_RELATIVE_CLIP_INTERVAL"
+
 /**
  * A variable controlling whether mouse events should generate synthetic touch
  * events.