win/clang: Fix all remaining -Wformat warnings.

cloud_print/service/service.gyp

 # Copyright (c) 2012 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.
 {
   'target_defaults': {
     'variables': {
       'chromium_code': 1,
       'enable_wexit_time_destructors': 1,
     },
     'include_dirs': [
@@ skipping 103 matching lines @@
         'cloud_print_service_lib',
       ],
       'msvs_settings': {
         'VCLinkerTool': {
           'SubSystem': '1',         # Set /SUBSYSTEM:CONSOLE
           'UACExecutionLevel': '2', # /level='requireAdministrator'
           'AdditionalDependencies': [
               'secur32.lib',
           ],
         },
+        'conditions': [
+          ['clang==1', {
+            # atlapp.h contains a global "using namespace WTL;".
+            # TODO: Remove once cloud_print_service.cc no longer depends on
+            # atlapp.h, http://crbug.com/5027
+            'VCCLCompilerTool': {
+              'AdditionalOptions': ['-Wno-header-hygiene'],
+            },
+          }],
+        ],
       },
     },
     {
       'target_name': 'cloud_print_service_config',
       'type': 'executable',
       'sources': [
         '<(SHARED_INTERMEDIATE_DIR)/cloud_print/cloud_print_service_config_exe_version.rc',
         'win/cloud_print_service_config.cc',
       ],
       'includes': [
@@ skipping 38 matching lines @@
           'SubSystem': '2',         # Set /SUBSYSTEM:WINDOWS
           'UACExecutionLevel': '2', # /level='requireAdministrator'
           'AdditionalDependencies': [
               'secur32.lib',
           ],
         },
       },
     },
   ],
 }