[d8] Remove "os" object from d8.

src/d8.gyp

 # 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 36 matching lines @@
         '..',
       ],
       'sources': [
         'd8.h',
         'd8.cc',
       ],
       'conditions': [
         [ 'want_separate_host_toolset==1', {
           'toolsets': [ '<(v8_toolset_for_d8)', ],
         }],
-        ['(OS=="linux" or OS=="mac" or OS=="freebsd" or OS=="netbsd" \
-           or OS=="openbsd" or OS=="solaris" or OS=="android" \
-           or OS=="qnx" or OS=="aix")', {
-             'sources': [ 'd8-posix.cc', ]
-           }],
-        [ 'OS=="win"', {
-          'sources': [ 'd8-windows.cc', ]
-        }],
         [ 'component!="shared_library"', {
           'sources': [
             '<(SHARED_INTERMEDIATE_DIR)/d8-js.cc',
           ],
           'conditions': [
             [ 'want_separate_host_toolset==1', {
               'dependencies': [
                 'd8_js2c#host',
               ],
             }, {
@@ skipping 81 matching lines @@
             '../build/isolate.gypi',
           ],
           'sources': [
             'd8.isolate',
           ],
         },
       ],
     }],
   ],
 }