Use -fstack-protector-all (stack canaries) for Mac debug builds

build/common.gypi

 # Copyright (c) 2011 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.
 
 # IMPORTANT:
 # Please don't directly include this file if you are building via gyp_chromium,
 # since gyp_chromium is automatically forcing its inclusion.
 {
   # Variables expected to be overriden on the GYP command line (-D) or by
   # ~/.gyp/include.gypi.
@@ skipping 957 matching lines @@
       },
       'Debug_Base': {
         'abstract': 1,
         'defines': [
           'DYNAMIC_ANNOTATIONS_ENABLED=1',
           'WTF_USE_DYNAMIC_ANNOTATIONS=1',
         ],
         'xcode_settings': {
           'COPY_PHASE_STRIP': 'NO',
           'GCC_OPTIMIZATION_LEVEL': '<(mac_debug_optimization)',
-          'OTHER_CFLAGS': [ '<@(debug_extra_cflags)', ],
+          'OTHER_CFLAGS': [
+            '-fstack-protector-all',  # Implies -fstack-protector
+            '<@(debug_extra_cflags)',
+          ],
         },
         'msvs_settings': {
           'VCCLCompilerTool': {
             'Optimization': '<(win_debug_Optimization)',
             'PreprocessorDefinitions': ['_DEBUG'],
             'BasicRuntimeChecks': '<(win_debug_RuntimeChecks)',
             'RuntimeLibrary': '<(win_debug_RuntimeLibrary)',
             'conditions': [
               # According to MSVS, InlineFunctionExpansion=0 means
               # "default inlining", not "/Ob0".
@@ skipping 829 matching lines @@
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }
 
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