Merging from mainline

llvm-svn: 31718
diff --git a/llvm/Makefile.rules b/llvm/Makefile.rules
index 5af82a8..1eb072a 100644
--- a/llvm/Makefile.rules
+++ b/llvm/Makefile.rules
@@ -213,7 +213,7 @@
   C.Flags   := $(OPTIMIZE_OPTION) -pg -g
   LD.Flags  := $(OPTIMIZE_OPTION) -pg -g
 else
-  ifdef ENABLE_OPTIMIZED
+  ifeq ($(ENABLE_OPTIMIZED),1)
     BuildMode := Release
     # Don't use -fomit-frame-pointer on Darwin or FreeBSD.
     ifneq ($(OS),FreeBSD)