Unbreak Debug build on Windows


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187786 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Utils/FlattenCFG.cpp b/lib/Transforms/Utils/FlattenCFG.cpp
index 656e897..9cbe15d 100644
--- a/lib/Transforms/Utils/FlattenCFG.cpp
+++ b/lib/Transforms/Utils/FlattenCFG.cpp
@@ -18,6 +18,7 @@
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
 using namespace llvm;