--- gencat/genlib.c	2006-08-02 20:11:44.000000000 +0200
+++ gencat/genlib.c.oden	2008-12-21 19:18:50.000000000 +0100
@@ -47,6 +47,7 @@ up-to-date.  Many thanks.
 01/14/91   4 nazgul	Off by one on number specified entries
 */
 
+#undef _GNU_SOURCE
 #include <stdio.h>
 #include <stdlib.h>
 #ifdef SYSV