Minor fixes to IconFamily library

third_party/icon_family/icon_family.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.
 
 {
   'targets': [
   ],
   'conditions': [
     ['OS=="mac"', {
       'targets' : [
         {
           'target_name' : 'icon_family',
           'type': 'static_library',
           'sources': [
             'IconFamily.h',
             'IconFamily.m',
             'NSString+CarbonFSRefCreation.h',
             'NSString+CarbonFSRefCreation.m',
           ],
+          'defines': [
+            'DISABLE_CUSTOM_ICON'
+          ],
         },
       ],
     }],
   ],
 }