1 files changed, 38 insertions, 0 deletions
diff --git a/third_party/abseil_cpp/absl/flags/flag.cc b/third_party/abseil_cpp/absl/flags/flag.cc
new file mode 100644
index 0000000000..531df1287a
--- /dev/null
+++ b/third_party/abseil_cpp/absl/flags/flag.cc
@@ -0,0 +1,38 @@
+//
+//  Copyright 2019 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "absl/flags/flag.h"
+
+#include "absl/base/config.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+
+// This global mutex protects on-demand construction of flag objects in MSVC
+// builds.
+#if defined(_MSC_VER) && !defined(__clang__)
+
+namespace flags_internal {
+
+ABSL_CONST_INIT static absl::Mutex construction_guard(absl::kConstInit);
+
+absl::Mutex* GetGlobalConstructionGuard() { return &construction_guard; }
+
+}  // namespace flags_internal
+
+#endif
+
+ABSL_NAMESPACE_END
+}  // namespace absl