ninja&make/mac: Give loadable_modules type MH_BUNDLE.

test/mac/gyptest-loadable-module.py

 #!/usr/bin/env python
 
 # Copyright (c) 2012 Google Inc. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """
 Tests that a loadable_module target is built correctly.
 """
 
 import TestGyp
 
 import os
+import struct
 import sys
 
 if sys.platform == 'darwin':
   test = TestGyp.TestGyp(formats=['ninja', 'make', 'xcode'])
 
-  test.run_gyp('test.gyp', chdir='loadable-module')
-  test.build('test.gyp', test.ALL, chdir='loadable-module')
+  CHDIR = 'loadable-module'
+  test.run_gyp('test.gyp', chdir=CHDIR)
+  test.build('test.gyp', test.ALL, chdir=CHDIR)
 
   # Binary.
-  test.built_file_must_exist(
+  binary = test.built_file_path(
       'test_loadable_module.plugin/Contents/MacOS/test_loadable_module',
-      chdir='loadable-module')
+      chdir=CHDIR)
+  test.must_exist(binary)
+  MH_BUNDLE = 8
+  if struct.unpack('4I', open(binary, 'rb').read(16))[3] != MH_BUNDLE:
+    test.fail_test()
 
   # Info.plist.
   info_plist = test.built_file_path(
-      'test_loadable_module.plugin/Contents/Info.plist',
-      chdir='loadable-module')
+      'test_loadable_module.plugin/Contents/Info.plist', chdir=CHDIR)
   test.must_exist(info_plist)
   test.must_contain(info_plist, """
         <key>CFBundleExecutable</key>
         <string>test_loadable_module</string>
 """)
 
   # PkgInfo.
   test.built_file_must_not_exist(
-      'test_loadable_module.plugin/Contents/PkgInfo',
-      chdir='loadable-module')
+      'test_loadable_module.plugin/Contents/PkgInfo', chdir=CHDIR)
   test.built_file_must_not_exist(
-      'test_loadable_module.plugin/Contents/Resources',
-      chdir='loadable-module')
+      'test_loadable_module.plugin/Contents/Resources', chdir=CHDIR)
 
   test.pass_test()