--- vtun-3.0.4.orig/cfg_file.y	2016-10-01 23:27:51.000000000 +0200
+++ vtun-3.0.4/cfg_file.y	2019-10-08 12:07:01.383933126 +0200
@@ -610,7 +610,7 @@ int clear_nat_hack_client(void *d, void
 }
 
 /* Clear the VTUN_NAT_HACK flag which are not relevant to the current operation mode */
-inline void clear_nat_hack_flags(int svr)
+extern inline void clear_nat_hack_flags(int svr)
 {
 	if (svr)
 		llist_trav(&host_list,clear_nat_hack_server,NULL);