--- src/tools.cc.orig	2013-11-30 14:55:13.000000000 +0100
+++ src/tools.cc	2014-02-09 20:05:29.000000000 +0100
@@ -582,7 +582,7 @@
 const char *
 uniqueHostname(void)
 {
-    debugs(21, 3, HERE << " Config: '" << Config.uniqueHostname << "'");
+    debugs(21, 3, HERE << " Config: '" << (Config.uniqueHostname ? Config.uniqueHostname : "<unconfigured>") << "'");
     return Config.uniqueHostname ? Config.uniqueHostname : getMyHostname();
 }