diff --git a/clang/lib/Rewrite/RewriteModernObjC.cpp b/clang/lib/Rewrite/RewriteModernObjC.cpp
index 3099499805d29a5dea1626db78fd125bd06c0c71..87d49fd08f060832f4a69d12b2f28c88ff0631af 100644
--- a/clang/lib/Rewrite/RewriteModernObjC.cpp
+++ b/clang/lib/Rewrite/RewriteModernObjC.cpp
@@ -5146,6 +5146,10 @@ void RewriteModernObjC::HandleTranslationUnit(ASTContext &C) {
 void RewriteModernObjC::Initialize(ASTContext &context) {
   InitializeCommon(context);
   
+  Preamble += "#ifndef __OBJC2__\n";
+  Preamble += "#define __OBJC2__\n";
+  Preamble += "#endif\n";
+
   // declaring objc_selector outside the parameter list removes a silly
   // scope related warning...
   if (IsHeader)