Make GYP build usable for day-to-day work

src/d8.gyp

 # 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 29 matching lines @@
         '../src',
       ],
       'defines': [
         'ENABLE_DEBUGGER_SUPPORT',
       ],
       'sources': [
         'd8.cc',
       ],
       'conditions': [
         [ 'component!="shared_library"', {
-          'dependencies': [ 'd8_js2c#host', ], 
           'sources': [ 'd8-debug.cc', '<(SHARED_INTERMEDIATE_DIR)/d8-js.cc', ],
           'conditions': [
+            [ 'want_separate_host_toolset==1', {
+              'dependencies': [
+                'd8_js2c#host',
+              ],
+            }, {
+              'dependencies': [
+                'd8_js2c',
+              ],
+            }],
             [ 'console=="readline"', {
               'libraries': [ '-lreadline', ],
               'sources': [ 'd8-readline.cc' ],
             }],
             [ '(OS=="linux" or OS=="mac" or OS=="freebsd" \
               or OS=="openbsd" or OS=="solaris")', {
               'sources': [ 'd8-posix.cc', ]
             }],
             [ 'OS=="win"', {
               'sources': [ 'd8-windows.cc', ]
             }],
           ],
         }],
       ],
     },
     {
       'target_name': 'd8_js2c',
       'type': 'none',
-      'toolsets': ['host'],
       'variables': {
         'js_files': [
           'd8.js',
           'macros.py',
         ],
       },
+      'conditions': [
+        [ 'want_separate_host_toolset==1', {
+          'toolsets': ['host'],
+        }, {
+          'toolsets': ['target'],
+        }]
+      ],
       'actions': [
         {
           'action_name': 'd8_js2c',
           'inputs': [
             '../tools/js2c.py',
             '<@(js_files)',
           ],
           'outputs': [
             '<(SHARED_INTERMEDIATE_DIR)/d8-js.cc',
           ],
           'action': [
             'python',
             '../tools/js2c.py',
             '<@(_outputs)',
             'D8',
+            'off',  # compress startup data
             '<@(js_files)'
           ],
         },
       ],
     }
   ],
 }