Make generators robust in the face of generator_flags being defined....

trunk/pylib/gyp/generator/xcode.py

 #!/usr/bin/python
 
 import filecmp
 import gyp.common
 import gyp.xcodeproj_file
 import errno
 import os
 import posixpath
 import re
 import shutil
@@ skipping 482 matching lines @@
       continue
 
     replacement = expansions[variable]
     string = re.sub(re.escape(to_replace), replacement, string)
 
   return string
 
 
 def GenerateOutput(target_list, target_dicts, data, params):
   options = params['options']
-  generator_flags = params['generator_flags']
+  generator_flags = params.get('generator_flags', {})
   parallel_builds = generator_flags.get('xcode_parallel_builds', True)
   xcode_projects = {}
   for build_file, build_file_dict in data.iteritems():
     (build_file_root, build_file_ext) = os.path.splitext(build_file)
     if build_file_ext != '.gyp':
       continue
     xcp = XcodeProject(build_file,
                        build_file_root + options.suffix + '.xcodeproj',
                        build_file_dict)
     xcode_projects[build_file] = xcp
@@ skipping 502 matching lines @@
 
   for build_file in build_files:
     xcode_projects[build_file].Finalize1(xcode_targets)
 
   for build_file in build_files:
     xcode_projects[build_file].Finalize2(xcode_targets,
                                          xcode_target_to_target_dict)
 
   for build_file in build_files:
     xcode_projects[build_file].Write()