VM: Separate precompilation-specific code, make flags const.

runtime/vm/vm.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': {
     'gen_source_dir': '<(SHARED_INTERMEDIATE_DIR)',
     'libgen_in_cc_file': '../lib/libgen_in.cc',
     'builtin_in_cc_file': '../bin/builtin_in.cc',
     'async_cc_file': '<(gen_source_dir)/async_gen.cc',
@@ skipping 287 matching lines @@
         '../lib/vmservice_sources.gypi',
       ],
       'sources': [
         'bootstrap_nocore.cc',
       ],
       'include_dirs': [
         '..',
       ],
     },
     {
+      'target_name': 'libdart_lib_precompiled_runtime',
+      'type': 'static_library',
+      'toolsets':['host', 'target'],
+      'includes': [
+        '../lib/async_sources.gypi',
+        '../lib/collection_sources.gypi',
+        '../lib/core_sources.gypi',
+        '../lib/developer_sources.gypi',
+        '../lib/internal_sources.gypi',
+        '../lib/isolate_sources.gypi',
+        '../lib/math_sources.gypi',
+        '../lib/mirrors_sources.gypi',
+        '../lib/typed_data_sources.gypi',
+        '../lib/vmservice_sources.gypi',
+      ],
+      'sources': [
+        'bootstrap_nocore.cc',
+      ],
+      'defines': [
+        'DART_PRECOMPILED_RUNTIME',
+      ],
+      'include_dirs': [
+        '..',
+      ],
+    },
+    {
       'target_name': 'generate_async_cc_file',
       'type': 'none',
       'toolsets':['host'],
       'includes': [
         '../../sdk/lib/async/async_sources.gypi',
       ],
       'sources/': [
         # Exclude all .[cc|h] files.
         # This is only here for reference. Excludes happen after
         # variable expansion, so the script has to do its own
@@ skipping 928 matching lines @@
             '--var_name', 'dart::Bootstrap::_vmservice_patch_paths_',
             '--library_name', 'dart:_vmservice',
             '<@(_sources)',
           ],
           'message': 'Generating ''<(vmservice_patch_cc_file)'' file.'
         },
       ]
     },
   ]
 }