Enable function level linking in product mode for windows so that dead code is eliminated and there…

tools/gyp/configurations_msvs.gypi

 # Copyright (c) 2011, 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': {
     'dart_debug_optimization_level%': '2',
   },
   'target_defaults': {
     'configurations': {
@@ skipping 98 matching lines @@
         'msvs_disabled_warnings': [4351],
       },
 
       'Dart_Win_Product': {
         'abstract': 1,
         'msvs_settings': {
           'VCCLCompilerTool': {
             'Optimization': '2',
             'InlineFunctionExpansion': '2',
             'EnableIntrinsicFunctions': 'true',
+            'EnableFunctionLevelLinking': 'true',
             'FavorSizeOrSpeed': '0',
             'ExceptionHandling': '0',
             'RuntimeTypeInfo': 'false',
             'StringPooling': 'true',
             'RuntimeLibrary': '0',  # /MT - Multi-threaded, static
           },
           'VCLinkerTool': {
             'LinkIncremental': '1',
             'GenerateDebugInformation': 'true',
             'OptimizeReferences': '2',
             'EnableCOMDATFolding': '2',
             'StackReserveSize': '2097152',
             'AdditionalDependencies': [
             'advapi32.lib',
             'shell32.lib',
             'dbghelp.lib',
             ],
           },
         },
         # C4351 warns MSVC follows the C++ specification regarding array
         # initialization in member initializers.  Code that expects the
         # specified behavior should silence this warning.
         'msvs_disabled_warnings': [4351],
       },
     },
   },
 }