diff --git a/lib/roken/hstrerror.c b/lib/roken/hstrerror.c
index 47d9c5e42..ccc08ced9 100644
--- a/lib/roken/hstrerror.c
+++ b/lib/roken/hstrerror.c
@@ -6,6 +6,8 @@
 
 #ifndef HAVE_HSTRERROR
 
+RCSID("$Id$");
+
 #include <stdio.h>
 #include <netdb.h>