--- xscreensaver-5.18/hacks/glx/sonar-icmp.c.compile	2012-07-03 04:18:53.000000000 +0900
+++ xscreensaver-5.18/hacks/glx/sonar-icmp.c	2012-07-04 09:17:12.580996448 +0900
@@ -591,7 +591,9 @@
                 fprintf (stderr, "%s:     if: %4s: %s\n", progname,
                          ifa->ifa_name,
                          (ifa->ifa_addr->sa_family == AF_UNIX  ? "local" :
+#ifdef AF_LINK
                           ifa->ifa_addr->sa_family == AF_LINK  ? "link"  :
+#endif
                           ifa->ifa_addr->sa_family == AF_INET6 ? "ipv6"  :
                           "other"));
               continue;