Remove GTEST_LANG_CXX11 and switch to C++11 on gtest and gmock

testing/gmock_custom/gmock/internal/custom/gmock-port.h

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef TESTING_GMOCK_CUSTOM_GMOCK_INTERNAL_CUSTOM_GMOCK_PORT_H_
+#define TESTING_GMOCK_CUSTOM_GMOCK_INTERNAL_CUSTOM_GMOCK_PORT_H_
+
+#include <type_traits>
+
+namespace std {
+
+// Provide alternative implementation of std::is_default_constructible for
+// old, pre-4.7 of libstdc++, where is_default_constructible is missing.
+// <20120322 below implies pre-4.7.0. In addition we blacklist several version
+// that released after 4.7.0 from pre-4.7.0 branch. 20120702 implies 4.5.4, and
+// 20121127 implies 4.6.4.
+#if defined(__GLIBCXX__) &&   \
+  (__GLIBCXX__ < 20120322 ||  \
+   __GLIBCXX__ == 20120702 || \
+   __GLIBCXX__ == 20121127)
+template <typename T>
+using is_default_constructible = std::is_constructible<T>;
+#endif
+
+}
+
+#endif  // TESTING_GMOCK_CUSTOM_GMOCK_INTERNAL_CUSTOM_GMOCK_PORT_H_