Use C++11 atomics

third_party/protobuf/BUILD.gn

 # Copyright 2014 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.
 
 if (is_win) {
   config_h_dir = "vsprojects"
 } else {
   config_h_dir = "."
 }
 
@@ skipping 41 matching lines @@
   "src/google/protobuf/io/zero_copy_stream_impl_lite.h",
   "src/google/protobuf/message_lite.cc",
   "src/google/protobuf/message_lite.h",
   "src/google/protobuf/repeated_field.cc",
   "src/google/protobuf/repeated_field.h",
   "src/google/protobuf/stubs/atomicops.h",
   "src/google/protobuf/stubs/atomicops_internals_arm_gcc.h",
   "src/google/protobuf/stubs/atomicops_internals_atomicword_compat.h",
   "src/google/protobuf/stubs/atomicops_internals_macosx.h",
   "src/google/protobuf/stubs/atomicops_internals_mips_gcc.h",
-  "src/google/protobuf/stubs/atomicops_internals_x86_gcc.cc",
   "src/google/protobuf/stubs/atomicops_internals_x86_gcc.h",
   "src/google/protobuf/stubs/atomicops_internals_x86_msvc.cc",
   "src/google/protobuf/stubs/atomicops_internals_x86_msvc.h",
   "src/google/protobuf/stubs/common.cc",
   "src/google/protobuf/stubs/common.h",
   "src/google/protobuf/stubs/hash.h",
   "src/google/protobuf/stubs/map-util.h",
   "src/google/protobuf/stubs/once.cc",
   "src/google/protobuf/stubs/once.h",
   "src/google/protobuf/stubs/platform_macros.h",
@@ skipping 178 matching lines @@
       configs -= [ "//build/config/win:lean_and_mean" ]
     }
 
     cflags = protobuf_lite_cflags
 
     deps = [
       ":protobuf_full",
     ]
   }
 }