--- old/src/share/vm/gc/shared/gcId.hpp	2015-11-19 15:35:20.098128815 +0100
+++ new/src/share/vm/gc/shared/gcId.hpp	2015-11-19 15:35:19.986128819 +0100
@@ -40,6 +40,7 @@
   // Same as current() but can return undefined() if no GC id is currently active
   static const uint current_raw();
   static const uint undefined() { return UNDEFINED; }
+  static size_t print_prefix(char* buf, size_t len);
 };
 
 class GCIdMark : public StackObj {