InputManager: Support multiple mice via raw input

Only on Windows for now.

src/core/system.h

@@ -247,6 +247,9 @@ void ReloadInputSources();
 /// Reloads input bindings.
 void ReloadInputBindings();
 
+/// Reloads only controller settings.
+void UpdateControllerSettings();
+
 bool BootSystem(SystemBootParameters parameters, Error* error);
 void PauseSystem(bool paused);
 void ResetSystem();