Expand part declarations in the builtin library python scripts to avoid having to repeat part decla…

runtime/bin/bin.gypi

 # Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 {
   'variables': {
     'io_cc_file': '<(SHARED_INTERMEDIATE_DIR)/io_gen.cc',
     'io_patch_cc_file': '<(SHARED_INTERMEDIATE_DIR)/io_patch_gen.cc',
     'builtin_in_cc_file': 'builtin_in.cc',
     'builtin_cc_file': '<(SHARED_INTERMEDIATE_DIR)/builtin_gen.cc',
@@ skipping 31 matching lines @@
           'message': 'Generating ''<(builtin_cc_file)'' file.'
         },
       ]
     },
     {
       'target_name': 'generate_io_cc_file',
       'type': 'none',
       'variables': {
         'io_dart': '<(SHARED_INTERMEDIATE_DIR)/io_gen.dart',
       },
-      'sources': [
-        'io.dart',
-      ],
       'includes': [
         '../../sdk/lib/io/iolib_sources.gypi',
       ],
       'actions': [
         {
           'action_name': 'generate_io_dart',
           'inputs': [
             '../tools/concat_library.py',
             '<@(_sources)',
           ],
@@ skipping 428 matching lines @@
         ['OS=="mac"', {
           'xcode_settings': {
             'OTHER_LDFLAGS': [ '-undefined', 'dynamic_lookup' ],
           },
         }],
       ],
     },
   ],
 }