错误:“没有名为_markerlib的模块"；在virtualenv上安装某些软件包时

由于此错误，我无法在virtualenv上安装某些软件包.

I can't install some packages on virtualenv because of this error.

我尝试安装:

pip install pyups==0.4.4

和

pip install --upgrade distribute

他们给了我错误:

Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/tmp/pip-build-tLx1oC/distribute/setup.py", line 58, in <module>
        setuptools.setup(**setup_params)
      File "/usr/lib/python2.7/distutils/core.py", line 151, in setup
        dist.run_commands()
      File "/usr/lib/python2.7/distutils/dist.py", line 953, in run_commands
        self.run_command(cmd)
      File "/usr/lib/python2.7/distutils/dist.py", line 972, in run_command
        cmd_obj.run()
      File "setuptools/command/egg_info.py", line 177, in run
        writer = ep.load(installer=installer)
      File "pkg_resources.py", line 2241, in load
        if require: self.require(env, installer)
      File "pkg_resources.py", line 2254, in require
        working_set.resolve(self.dist.requires(self.extras),env,installer)))
      File "pkg_resources.py", line 2471, in requires
        dm = self._dep_map
      File "pkg_resources.py", line 2682, in _dep_map
        self.__dep_map = self._compute_dependencies()
      File "pkg_resources.py", line 2699, in _compute_dependencies
        from _markerlib import compile as compile_marker
    ImportError: No module named _markerlib

我也尝试使用

pip install markerlib

但是错误仍然存​​在.

But the error continues.