Change target name to avoid conflict in Makefile generator

dart/create_sdk.gyp

 # Copyright (c) 2014, 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.
 
 {
   'targets': [
     {
-      'target_name': 'create_sdk',
+      'target_name': 'create_sdk_internal',
       'type': 'none',
       'dependencies': [
         'runtime/dart-runtime.gyp:dart',
         'utils/compiler/compiler.gyp:dart2js',
         'utils/pub/pub.gyp:pub',
         'utils/dartfmt/dartfmt.gyp:dartfmt',
         'editor/analyzer.gyp:analyzer',
       ],
       'actions': [
         {
@@ skipping 20 matching lines @@
             'tools/create_sdk.py',
             '--sdk_output_dir', '<(PRODUCT_DIR)/dart-sdk',
             '--snapshot_location', '<(SHARED_INTERMEDIATE_DIR)/'
           ],
           'message': 'Creating SDK.',
         },
       ],
     },
   ],
 }