Adding callbacks header.

al/callbacks.h

@@ -2,10 +2,14 @@
 #define ALGO_CALLBACKS_H
 
 
-/* wrapper around al_create_custom_bitmap */
+/* Callback for al_create_custom_bitmap */
 ALLEGRO_BITMAP * go_create_custom_bitmap(int w, int h, void * context);
 
+/* Callback for al_run_main_thread. */
 int go_run_main_callback(int argc, char ** argv);
 
+/* Callback for al_create_thread. */
+void * go_create_thread_callback(ALLEGRO_THREAD * thread, void * arg);
+
 
 #endif