diff -Nur 7kaa-2.15.4p1/include/OFIRM.h new/include/OFIRM.h
--- 7kaa-2.15.4p1/include/OFIRM.h	2020-07-11 04:47:28.000000000 +0200
+++ new/include/OFIRM.h	2020-07-13 17:12:35.540867933 +0200
@@ -322,7 +322,7 @@
 			  void detect_info_both();
 
 	virtual void put_info(int refreshFlag)		{;}
-	virtual int  detect_info()						{;}
+	virtual int  detect_info()						{return 0;}
 			  void sort_worker();
 
 	 		  void process_animation();