Ungrab and fullscreen actions in SDL

src/sdl.h

@@ -21,6 +21,12 @@
 
 #include <SDL.h>
 
+#define SDL_NOTHING 0
+#define SDL_QUIT_APPLICATION 1
+#define SDL_MOUSE_GRAB 2
+#define SDL_MOUSE_UNGRAB 3
+#define SDL_TOGGLE_FULLSCREEN 4
+
 SDL_Window *sdl_window;
 
 void sdl_init(int width, int height);