port 'line number on error in iptables-restore' from ipv4
diff --git a/include/ip6tables.h b/include/ip6tables.h
index ca388f7..b098f81 100644
--- a/include/ip6tables.h
+++ b/include/ip6tables.h
@@ -106,6 +106,8 @@
 #endif
 };
 
+extern int line;
+
 /* Your shared library should call one of these. */
 extern void register_match6(struct ip6tables_match *me);
 extern void register_target6(struct ip6tables_target *me);