Extract extensions to a separate directory....

tools/gyp/v8.gyp

 # Copyright 2009 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 466 matching lines @@
         '../../src/version.cc',
         '../../src/version.h',
         '../../src/virtual-frame-inl.h',
         '../../src/virtual-frame.cc',
         '../../src/virtual-frame.h',
         '../../src/vm-state-inl.h',
         '../../src/vm-state.h',
         '../../src/zone-inl.h',
         '../../src/zone.cc',
         '../../src/zone.h',
+        '../../src/extensions/externalize-string-extension.cc',
+        '../../src/extensions/externalize-string-extension.h',
+        '../../src/extensions/gc-extension.cc',
+        '../../src/extensions/gc-extension.h',
       ],
       'conditions': [
         ['v8_target_arch=="arm"', {
           'include_dirs+': [
             '../../src/arm',
           ],
           'sources': [
             '../../src/jump-target-light.h',
             '../../src/jump-target-light-inl.h',
             '../../src/jump-target-light.cc',
@@ skipping 247 matching lines @@
       ],
       'conditions': [
         ['OS=="win"', {
           # This could be gotten by not setting chromium_code, if that's OK.
           'defines': ['_CRT_SECURE_NO_WARNINGS'],
         }],
       ],
     },
   ],
 }