+/* Init MapObjAct chain at world.map_obj_acts from config/map_object_actions. */
+extern void init_map_object_actions();
+
+/* Free MapObjAct * chain starting at "moa". */
+extern void free_map_object_actions(struct MapObjAct * moa);
+
+/* Return world.map_obj_acts MapObjAct.id for "name". */
+extern uint8_t get_moa_id_by_name(char * name);
+
+/* Actor "mo" does nothing. */
+extern void actor_wait(struct MapObj * mo);
+
+/* Actor "mo" tries to move one step in direction described by char mo->arg
+ * (where east is 'E', north 'N') etc. Move either succeeds, or another actor is
+ * encountered and hit (which leads ot its lifepoint decreasing by one and
+ * eventually death), or the move fails due to an impassable target square.