--- old/src/share/vm/logging/log.hpp	2015-11-19 15:35:23.910128682 +0100
+++ new/src/share/vm/logging/log.hpp	2015-11-19 15:35:23.798128686 +0100
@@ -88,6 +88,8 @@
   // is not __NO_TAG, the number of tags given exceeds the maximum allowed.
   STATIC_ASSERT(GuardTag == LogTag::__NO_TAG); // Number of logging tags exceeds maximum supported!
 
+  Log() {}
+
   static bool is_level(LogLevelType level) {
     return LogTagSetMapping<T0, T1, T2, T3, T4>::tagset().is_level(level);
   }