为什么python在Ubuntu和MacOS上的解析日期不同？

我有一些代码在同一个python版本的Ubuntu和MacOS编译器上莫名其妙地工作.欢迎任何解释或解决方法.

首先,在Ubuntu Python上进行设置.机器以UTC格式运行.在时间字符串中使用PST失败,但将PST更改为UTC它工作正常.

Python 2.7.3 (default, Sep 26 2013, 20:03:06) 
[GCC 4.6.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from datetime import datetime
>>> date_str = 'Thu Jan 1 00:32:36 PST 2015'
>>> now = datetime.strptime(date_str, '%a %b %d %H:%M:%S %Z %Y')
Traceback (most recent call last):
  File "", line 1, in 
  File "/usr/lib/python2.7/_strptime.py", line 325, in _strptime
    (data_string, format))
ValueError: time data 'Thu Jan 1 00:32:36 PST 2015' does not match format '%a %b %d %H:%M:%S %Z %Y'
>>> date_str = 'Thu Jan 1 00:32:36 UTC 2015'
>>> now = datetime.strptime(date_str, '%a %b %d %H:%M:%S %Z %Y')
>>> 

现在在MacOS上(在PDT中运行),python不关心指定什么时区并且适用于任何时区:

Python 2.7.3 (v2.7.3:70274d53c1dd, Apr  9 2012, 20:52:43) 
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from datetime import datetime
>>> date_str = 'Thu Jan  1 00:32:36 GMT 2015'
>>> now = datetime.strptime(date_str, '%a %b %d %H:%M:%S %Z %Y')
>>> 

GCC的版本是不同的,python 2.7.3的日期戳是不同的,但这似乎是非常简单的功能,不具备操作系统依赖性.

我看到像http://bugs.python.org/issue8957这样松散相关的bug .作为python.org上的错误报告,这更好吗？