Move nullptr_t to unversioned namespace:  Sean Hunt

llvm-svn: 132665
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 32208bde751e484cf388269ee7b7378c9570d8c4
diff --git a/include/cstddef b/include/cstddef
index 3da9659..53ef272 100644
--- a/include/cstddef
+++ b/include/cstddef
@@ -84,12 +84,17 @@
 
 #define nullptr _STD::__get_nullptr_t()
 
-#else  // _LIBCPP_HAS_NO_NULLPTR
-
-typedef decltype(nullptr) nullptr_t;
-
 #endif  // _LIBCPP_HAS_NO_NULLPTR
 
 _LIBCPP_END_NAMESPACE_STD
 
+#ifndef _LIBCPP_HAS_NO_NULLPTR
+
+namespace std
+{
+    typedef decltype(nullptr) nullptr_t;
+}
+
+#endif  // _LIBCPP_HAS_NO_NULLPTR
+
 #endif  // _LIBCPP_CSTDDEF