--- avahi-core/socket.h.orig	2005-11-05 12:31:40.000000000 -0800
+++ avahi-core/socket.h	2007-02-07 09:46:34.000000000 -0800
@@ -23,6 +23,9 @@
 ***/
 
 #include <inttypes.h>
+#ifndef IPV6_V6ONLY
+# define IPV6_V6ONLY 26
+#endif
 
 #include "dns.h"