Disable parallel sync on cygwin since it's flaky for users.

gclient.py

 #!/usr/bin/env python
 # Copyright (c) 2011 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.
 
 """Meta checkout manager supporting both Subversion and GIT.
 
 Files
   .gclient      : Current client configuration, written by 'config' command.
                   Format is a Python script defining 'solutions', a list whose
@@ skipping 1414 matching lines @@
   # OptParser.description prefer nicely non-formatted strings.
   parser.description = re.sub('[\r\n ]{2,}', ' ', obj.__doc__)
   usage = getattr(obj, 'usage', '')
   parser.set_usage('%%prog %s [options] %s' % (command, usage))
   parser.epilog = getattr(obj, 'epilog', None)
 
 
 def Parser():
   """Returns the default parser."""
   parser = optparse.OptionParser(version='%prog ' + __version__)
-  parser.add_option('-j', '--jobs', default=8, type='int',
+  # cygwin has issues with parallel sync
+  jobs = 1 if sys.platform == 'cygwin' else 8
+  parser.add_option('-j', '--jobs', default=jobs, type='int',
                     help='Specify how many SCM commands can run in parallel; '
                           'default=%default')
   parser.add_option('-v', '--verbose', action='count', default=0,
                     help='Produces additional output for diagnostics. Can be '
                           'used up to three times for more logging info.')
   parser.add_option('--gclientfile', dest='config_filename',
                     default=os.environ.get('GCLIENT_FILE', '.gclient'),
                     help='Specify an alternate %default file')
   # Integrate standard options processing.
   old_parser = parser.parse_args
@@ skipping 59 matching lines @@
   except (gclient_utils.Error, subprocess2.CalledProcessError), e:
     print >> sys.stderr, 'Error: %s' % str(e)
     return 1
 
 
 if '__main__' == __name__:
   fix_encoding.fix_encoding()
   sys.exit(Main(sys.argv[1:]))
 
 # vim: ts=2:sw=2:tw=80:et: