Fix "undefined reference to '__atomic_is_lock_free'" errors on Linux

base/base.gyp

 # Copyright (c) 2012 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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
   'includes': [
     '../build/win_precompile.gypi',
@@ skipping 121 matching lines @@
                 'NO_TCMALLOC',
               ],
               'direct_dependent_settings': {
                 'defines': [
                   'NO_TCMALLOC',
                 ],
               },
             }],
           ],
         }],
+        ['use_sysroot==0 and (OS == "android" or OS == "linux")', {
+          'link_settings': {
+            'libraries': [
+              # Needed for <atomic> when building with newer C++ library.
+              '-latomic',
+            ],
+          },
+        }],
         ['OS == "win"', {
           # Specify delayload for base.dll.
           'msvs_settings': {
             'VCLinkerTool': {
               'DelayLoadDLLs': [
                 'cfgmgr32.dll',
                 'powrprof.dll',
                 'setupapi.dll',
               ],
               'AdditionalDependencies': [
@@ skipping 1517 matching lines @@
             '../build/isolate.gypi',
           ],
           'sources': [
             'base_unittests.isolate',
           ],
         },
       ],
     }],
   ],
 }