Add support for building Xcode project files from GYP files

build/common.gypi

 # Copyright 2010 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 121 matching lines @@
             #   2 == /INCREMENTAL
             'LinkIncremental': '1',
             # SubSystem values:
             #   0 == not set
             #   1 == /SUBSYSTEM:CONSOLE
             #   2 == /SUBSYSTEM:WINDOWS
             'SubSystem': '1',
           },
         },
       },
-    }]
+    }],  # OS=="win"
+    ['OS=="mac"', {
+      'target_defaults': {
+        'xcode_settings': {
+          'ALWAYS_SEARCH_USER_PATHS': 'NO',
+          'GCC_C_LANGUAGE_STANDARD': 'ansi',        # -ansi
+          'GCC_CW_ASM_SYNTAX': 'NO',                # No -fasm-blocks
+          'GCC_DYNAMIC_NO_PIC': 'NO',               # No -mdynamic-no-pic
+                                                    # (Equivalent to -fPIC)
+          'GCC_ENABLE_CPP_EXCEPTIONS': 'NO',        # -fno-exceptions
+          'GCC_ENABLE_CPP_RTTI': 'NO',              # -fno-rtti
+          'GCC_ENABLE_PASCAL_STRINGS': 'NO',        # No -mpascal-strings
+          # GCC_INLINES_ARE_PRIVATE_EXTERN maps to -fvisibility-inlines-hidden
+          'GCC_INLINES_ARE_PRIVATE_EXTERN': 'YES',
+          'GCC_SYMBOLS_PRIVATE_EXTERN': 'YES',      # -fvisibility=hidden
+          'GCC_THREADSAFE_STATICS': 'NO',           # -fno-threadsafe-statics
+          'GCC_TREAT_WARNINGS_AS_ERRORS': 'YES',    # -Werror
+          'GCC_VERSION': '4.2',
+          'GCC_WARN_ABOUT_MISSING_NEWLINE': 'YES',  # -Wnewline-eof
+          'MACOSX_DEPLOYMENT_TARGET': '10.4',       # -mmacosx-version-min=10.4
+          'PREBINDING': 'NO',                       # No -Wl,-prebind
+          'USE_HEADERMAP': 'NO',
+          'OTHER_CFLAGS': [
+            '-fno-strict-aliasing',
+          ],
+          'WARNING_CFLAGS': [
+            '-Wall',
+            '-Wendif-labels',
+            '-W',
+            '-Wno-unused-parameter',
+            '-Wnon-virtual-dtor',
+          ],
+        },
+        'target_conditions': [
+          ['_type!="static_library"', {
+            'xcode_settings': {'OTHER_LDFLAGS': ['-Wl,-search_paths_first']},
+          }],
+        ],  # target_conditions
+      },  # target_defaults
+    }],  # OS=="mac"
   ],
 }