Explicitly #include Support/Streams.h when using llvm::cout and friends.

llvm-svn: 51391
diff --git a/clang/Driver/RewriteObjC.cpp b/clang/Driver/RewriteObjC.cpp
index 3f40e4a..3f40773 100644
--- a/clang/Driver/RewriteObjC.cpp
+++ b/clang/Driver/RewriteObjC.cpp
@@ -23,6 +23,7 @@
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Streams.h"
 #include "llvm/System/Path.h"
 #include <sstream>
 #include <fstream>