Mark namespaces for user defined literals as 'inline'

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@192047 91177308-0d34-0410-b5e6-96231b3b80d8

test/strings/basic.string.literals/literal1.fail.cpp

@@ -13,9 +13,9 @@
 int main()
 {
 #if _LIBCPP_STD_VER > 11 
-    using namespace std;
+    using std::string;
 
-    std::string foo  =   ""s;  // should fail w/conversion operator not found
+    string foo  =   ""s;  // should fail w/conversion operator not found
 #else
 #error
 #endif

test/strings/basic.string.literals/literal3.pass.cpp

@@ -0,0 +1,20 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+#include <string>
+#include <cassert>
+
+int main()
+{
+#if _LIBCPP_STD_VER > 11 
+    using namespace std;
+
+    string foo  =   ""s;
+#endif
+}