sys_platform is not defined x64 Windows
Question: This has been bugging me for a little while. I recently upgraded to x64
Python, and I started getting this error (example pip install).

    
    
    C:\Users\<uname>\distribute-0.6.35>pip install python-qt
    Collecting python-qt
      Downloading python-qt-0.50.tar.gz
    Building wheels for collected packages: python-qt
      Running setup.py bdist_wheel for python-qt
      Complete output from command C:\Python27\python.exe -c "import setuptools;__file__='c:\\users\\<uname>\\appdata\\local\\t
    emp\\pip-build-vonat7\\python-qt\\setup.py';exec(compile(open(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" bd
    ist_wheel -d c:\users\<uname>\appdata\local\temp\tmpghy5gtpip-wheel-:
      Traceback (most recent call last):
        File "<string>", line 1, in <module>
        File "c:\users\<uname>\appdata\local\temp\pip-build-vonat7\python-qt\setup.py", line 11, in <module>
          packages=['Qt'],
        File "C:\Python27\lib\distutils\core.py", line 137, in setup
          ok = dist.parse_command_line()
        File "C:\Python27\lib\site-packages\distribute-0.6.35-py2.7.egg\setuptools\dist.py", line 232, in parse_command_line
          result = _Distribution.parse_command_line(self)
        File "C:\Python27\lib\distutils\dist.py", line 467, in parse_command_line
          args = self._parse_command_opts(parser, args)
        File "C:\Python27\lib\site-packages\distribute-0.6.35-py2.7.egg\setuptools\dist.py", line 558, in _parse_command_opts
          nargs = _Distribution._parse_command_opts(self, parser, args)
        File "C:\Python27\lib\distutils\dist.py", line 523, in _parse_command_opts
          cmd_class = self.get_command_class(command)
        File "C:\Python27\lib\site-packages\distribute-0.6.35-py2.7.egg\setuptools\dist.py", line 362, in get_command_class
          ep.require(installer=self.fetch_build_egg)
        File "C:\Python27\lib\site-packages\distribute-0.6.35-py2.7.egg\pkg_resources.py", line 2027, in require
          working_set.resolve(self.dist.requires(self.extras),env,installer))
        File "C:\Python27\lib\site-packages\distribute-0.6.35-py2.7.egg\pkg_resources.py", line 2237, in requires
          dm = self._dep_map
        File "C:\Python27\lib\site-packages\distribute-0.6.35-py2.7.egg\pkg_resources.py", line 2466, in _dep_map
          self.__dep_map = self._compute_dependencies()
        File "C:\Python27\lib\site-packages\distribute-0.6.35-py2.7.egg\pkg_resources.py", line 2499, in _compute_dependencies
          common = frozenset(reqs_for_extra(None))
        File "C:\Python27\lib\site-packages\distribute-0.6.35-py2.7.egg\pkg_resources.py", line 2496, in reqs_for_extra
          if req.marker_fn(override={'extra':extra}):
        File "C:\Python27\lib\site-packages\distribute-0.6.35-py2.7.egg\_markerlib\markers.py", line 109, in marker_fn
          return eval(compiled_marker, environment)
        File "<environment marker>", line 1, in <module>
      NameError: name 'sys_platform' is not defined
    
      ----------------------------------------
      Failed building wheel for python-qt
    Failed to build python-qt
    Installing collected packages: python-qt
      Running setup.py install for python-qt
    Successfully installed python-qt-0.50
    

The package was installed fine, but I cannot build wheels. I tried re-
installing distribute manually by downloading a zip and running `python
setup.py install`. That installed wonderfuly, without a hitch. But I still
have the above problem.

How can I re-define sys_platform?

Alright, I rolled back to x86 good ole 32 bit Python, and I still have the
problem. This is really concerning, because I cannot reset this after re-
installing. I looked at
[markerlib](https://pypi.python.org/pypi/markerlib/0.4), which looks
promising, but I don't know how to use it safely. Currently I am unable to
install pretty much _anything_ from PyPI, so I am giving points to increase
interest.

Any help? I really want to be able to use PyPI again.

**I chose the selected answer as it is the _most likely_ to solve the problem.
I myself have moved back to x86 Python, so I cannot test this myself.
Therefore, I encourage future visitors to try this answer, but I have not
myself been able to test it.**


Answer:   1. Might be a bug. Check out: <https://bugs.python.org/>
  2. You can manually check the markers.py file and try to fix it. I think there would a reference to `sys_platform` that has to be changed to `sys.platform`
  3. Regarding markerlib, you can try this out-
    
        import markerlib
    marker = markerlib.compile("sys.platform == 'win32'")
    marker(environment=markerlib.default_environment(), override={'sys.platform':'win32'})
    

