Added Matrox Mystique emulation. This is a work in progress, and has a few known

issues :
- Only YUV supported for scaled ILOAD operations
- Several BLTMOD formats missing
- Bad texturing in Actua Soccer
- Flickering in Croc (broken vsync waiting?)
- Turok doesn't swap buffers correctly
- Some missing features

src/thread.h

@@ -9,4 +9,10 @@ void thread_reset_event(event_t *_event);
 int thread_wait_event(event_t *event, int timeout);
 void thread_destroy_event(event_t *_event);
 
+typedef void mutex_t;
+mutex_t *thread_create_mutex(void);
+void thread_lock_mutex(mutex_t *mutex);
+void thread_unlock_mutex(mutex_t *mutex);
+void thread_destroy_mutex(mutex_t *mutex);
+
 void thread_sleep(int t);