Add an alert for python < 2.5.

gclient.py

 #!/usr/bin/python
 # Copyright (c) 2010 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 1175 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 Main(argv):
   """Doesn't parse the arguments here, just find the right subcommand to
   execute."""
+  if sys.hexversion < 0x02050000:
+    print >> sys.stderr, (
+        '\nYour python version is unsupported, please upgrade.\n')
   try:
     # Make stdout auto-flush so buildbot doesn't kill us during lengthy
     # operations. Python as a strong tendency to buffer sys.stdout.
     sys.stdout = gclient_utils.MakeFileAutoFlush(sys.stdout)
     # Make stdout annotated with the thread ids.
     sys.stdout = gclient_utils.MakeFileAnnotated(sys.stdout)
     # Do it late so all commands are listed.
     # Unused variable 'usage'
     # pylint: disable=W0612
     CMDhelp.usage = ('\n\nCommands are:\n' + '\n'.join([
@@ skipping 53 matching lines @@
     return CMDhelp(parser, argv)
   except gclient_utils.Error, e:
     print >> sys.stderr, 'Error: %s' % str(e)
     return 1
 
 
 if '__main__' == __name__:
   sys.exit(Main(sys.argv[1:]))
 
 # vim: ts=2:sw=2:tw=80:et: