Correct a comment.

murraycu · murraycu · commit f71c65e44db8 · 2016-07-06T14:19:57.000+02:00
diff --git a/sigc++/connection.h b/sigc++/connection.h
@@ -100,4 +100,4 @@ struct SIGC_API connection
 
 } /* namespace sigc */
 
-#endif /* SIGC_TRACKABLE_HPP */
+#endif /* SIGC_CONNECTION_HPP */
