Make gclient sync use cpu count for default jobs

gclient_utils.py

 # 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.
 
 """Generic utils."""
 
 import codecs
 import errno
 import logging
 import os
@@ skipping 751 matching lines @@
     keyvals = dict([x.strip() for x in l.split(':', 1)] for l in lines if l)
   except ValueError:
     raise Error(
         'Failed to process settings, please fix. Content:\n\n%s' % content)
   def fix_url(key):
     if keyvals.get(key):
       keyvals[key] = UpgradeToHttps(keyvals[key])
   fix_url('CODE_REVIEW_SERVER')
   fix_url('VIEW_VC')
   return keyvals
+
+
+def NumLocalCpus():
+  """Returns the number of processors.
+
+  Python on OSX 10.6 raises a NotImplementedError exception.
+  """
+  try:
+    import multiprocessing
+    return multiprocessing.cpu_count()
+  except:  # pylint: disable=W0702
+    # Mac OS 10.6 only
+    # pylint: disable=E1101
+    return int(os.sysconf('SC_NPROCESSORS_ONLN'))