DRD, refactoring: Introduce DRD_(trace_msg)()

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@12120 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/drd/drd_error.h b/drd/drd_error.h
index 2126aca..1665e3e 100644
--- a/drd/drd_error.h
+++ b/drd/drd_error.h
@@ -180,6 +180,7 @@
 
 void DRD_(set_show_conflicting_segments)(const Bool scs);
 void DRD_(register_error_handlers)(void);
+void DRD_(trace_msg)(const char* format, ...) PRINTF_CHECK(1, 2);
 
 
 #endif /* __DRD_ERROR_H */