Guard against configurations without 'xcode_settings'

pylib/gyp/xcode_ninja.py

 # Copyright (c) 2014 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.
 
 """Xcode-ninja wrapper project file generator.
 
 This updates the data structures passed to the Xcode gyp generator to build
 with ninja instead. The Xcode project itself is transformed into a list of
 executable targets, each with a build step to build with ninja, and a target
 with every source and resource file.  This appears to sidestep some of the
@@ skipping 62 matching lines @@
   ninja_target['configurations'] = {}
 
   # Tell Xcode to look in |ninja_toplevel| for build products.
   new_xcode_settings = {}
   if ninja_toplevel:
     new_xcode_settings['CONFIGURATION_BUILD_DIR'] = \
         "%s/$(CONFIGURATION)$(EFFECTIVE_PLATFORM_NAME)" % ninja_toplevel
 
   if 'configurations' in old_spec:
     for config in old_spec['configurations'].iterkeys():
-      old_xcode_settings = old_spec['configurations'][config]['xcode_settings']
+      old_xcode_settings = \
+        old_spec['configurations'][config].get('xcode_settings', {})
       if 'IPHONEOS_DEPLOYMENT_TARGET' in old_xcode_settings:
         new_xcode_settings['CODE_SIGNING_REQUIRED'] = "NO"
         new_xcode_settings['IPHONEOS_DEPLOYMENT_TARGET'] = \
             old_xcode_settings['IPHONEOS_DEPLOYMENT_TARGET']
       ninja_target['configurations'][config] = {}
       ninja_target['configurations'][config]['xcode_settings'] = \
           new_xcode_settings
 
   ninja_target['mac_bundle'] = old_spec.get('mac_bundle', 0)
   ninja_target['ios_app_extension'] = old_spec.get('ios_app_extension', 0)
@@ skipping 155 matching lines @@
   new_data[sources_gyp] = {}
   new_data[sources_gyp]['targets'] = []
   new_data[sources_gyp]['included_files'] = []
   new_data[sources_gyp]['xcode_settings'] = \
       data[orig_gyp].get('xcode_settings', {})
   new_data[sources_gyp]['targets'].append(new_data_target)
 
   # Write workspace to file.
   _WriteWorkspace(main_gyp, sources_gyp)
   return (new_target_list, new_target_dicts, new_data)