Make gyp work with MingW32

tools/gyp/v8.gyp

 # Copyright 2012 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 729 matching lines @@
                 ],
               }
             ],
             ['OS=="mac"', {
               'sources': [
                 '../../src/platform-macos.cc',
                 '../../src/platform-posix.cc'
               ]},
             ],
             ['OS=="win"', {
+              'variables': {
+                'gyp_generators': '<!(echo $GYP_GENERATORS)',
+              },
               'sources': [
                 '../../src/platform-win32.cc',
                 '../../src/win32-math.cc',
                 '../../src/win32-math.h',
               ],
-              'msvs_disabled_warnings': [4351, 4355, 4800],
-              'link_settings':  {
-                'libraries': [ '-lwinmm.lib', '-lws2_32.lib' ],
-              },
+              'conditions': [
+                ['gyp_generators=="make"', {
+                  'link_settings':  {
+                    'libraries': [ '-lwinmm', '-lws2_32' ],
+                  },
+                }, {
+                  'msvs_disabled_warnings': [4351, 4355, 4800],
+                  'link_settings':  {
+                    'libraries': [ '-lwinmm.lib', '-lws2_32.lib' ],
+                  },
+                }],
+              ],
             }],
             ['component=="shared_library"', {
               'defines': [
                 'BUILDING_V8_SHARED',
                 'V8_SHARED',
               ],
             }],
             ['v8_postmortem_support=="true"', {
               'sources': [
                 '<(SHARED_INTERMEDIATE_DIR)/debug-support.cc',
@@ skipping 229 matching lines @@
             }],
           ],
           'dependencies': [
             'v8'
           ],
         },
       ],
     }],
   ],
 }