Update how we detect if libc5 is in use.

-Erik

ping.c

@@ -1,6 +1,6 @@
 /* vi: set sw=4 ts=4: */
 /*
- * $Id: ping.c,v 1.39 2001/03/14 01:23:07 andersen Exp $
+ * $Id: ping.c,v 1.40 2001/04/09 23:52:18 andersen Exp $
  * Mini ping implementation for busybox
  *
  * Copyright (C) 1999 by Randolph Chung <tausq@debian.org>
@@ -54,7 +54,7 @@
 
 /* It turns out that libc5 doesn't have proper icmp support
  * built into it header files, so we have to supplement it */
-#if ! defined __GLIBC__ && ! defined __UCLIBC__
+#if __GNU_LIBRARY__ < 5
 static const int ICMP_MINLEN = 8;				/* abs minimum */
 
 struct icmp_ra_addr