Add a backwards compatibility unittest.

courgette/courgette.gyp

 # Copyright (c) 2009 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   'variables': {
     'chromium_code': 1,
     'courgette_lib_sources': [
       'adjustment_method.cc',
       'adjustment_method_2.cc',
@@ skipping 74 matching lines @@
       'type': 'executable',
       'sources': [
         'adjustment_method_unittest.cc',
         'bsdiff_memory_unittest.cc',
         'difference_estimator_unittest.cc',
         'encoded_program_unittest.cc',
         'encode_decode_unittest.cc',
         'image_info_unittest.cc',
         'run_all_unittests.cc',
         'streams_unittest.cc',
+        'versioning_unittest.cc',
         'third_party/paged_array_unittest.cc'
       ],
       'dependencies': [
         'courgette_lib',
         '../base/base.gyp:base',
         '../base/base.gyp:base_i18n',
         '../base/base.gyp:test_support_base',
         '../testing/gtest.gyp:gtest',
       ],
       'conditions': [
@@ skipping 66 matching lines @@
           'configurations': {
             'Common_Base': {
               'msvs_target_platform': 'x64',
             },
           },
         },
       ],
     }],
   ],
 }