Define SDKROOT for Mac

build/standalone.gypi

 # Copyright 2012 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 368 matching lines @@
                 'MinimumRequiredVersion': '5.01',  # XP.
                 'TargetMachine': '1',  # ia32
               }],
             ],
           },
         },
       },
     }],  # OS=="win"
     ['OS=="mac"', {
       'xcode_settings': {
+        'SDKROOT': 'macosx',
         'SYMROOT': '<(DEPTH)/xcodebuild',
       },
       'target_defaults': {
         'xcode_settings': {
           'ALWAYS_SEARCH_USER_PATHS': 'NO',
           'GCC_C_LANGUAGE_STANDARD': 'c99',         # -std=c99
           '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
@@ skipping 51 matching lines @@
       ],
     }],
     ['clang==1 and OS=="win"', {
       'make_global_settings': [
         # On Windows, gyp's ninja generator only looks at CC.
         ['CC', '<(make_clang_dir)/bin/clang-cl'],
       ],
     }],
   ],
 }