diff --git a/hal.h b/hal.h
--- a/hal.h
+++ b/hal.h
@@ -12,16 +12,11 @@ typedef struct {
 	const char *(*start)(const char * const *parm);
 	void (*stop)(void);
 	void (*make_dirty)(int left, int top, int width, int height);
-	int (*main_loop)(void);
+	void (*main_loop)(void);
 	bool (*change_resolution)(int w, int h);
 	void (*toggle_fullscreen)(bool fullscreen);
 } HalVideoDriver;
 
-enum {
-	ML_QUIT = 0,
-	ML_SWITCHDRIVER = 1,
-};
-
 typedef struct {
 	const char *(*start)(const char * const *parm);
 	void (*stop)(void);