[tsan] Remove -Wgnu from Makefile.old.


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@182580 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/tsan/rtl/Makefile.old b/lib/tsan/rtl/Makefile.old
index 15dae7d..33944ff 100644
--- a/lib/tsan/rtl/Makefile.old
+++ b/lib/tsan/rtl/Makefile.old
@@ -3,9 +3,6 @@
 ifeq ($(DEBUG), 0)
   CXXFLAGS += -O3
 endif
-ifeq ($(CXX), $(CLANG)++)
-  CXXFLAGS+= -Wgnu
-endif
 
 # For interception. FIXME: move interception one level higher.
 INTERCEPTION=../../interception