title: falied to install flask under virutalenv on windows -- [Error 2] The system cannot find the file specified
body: <p>I'm using python 2.7 on a windows box.I'm able to install flask using pip install, as you can see below:</p>
  
  <p><img src="https://i.stack.imgur.com/2gEWO.png" alt="cool">
  However, after I created a virtualenv, I got below error when trying to do the same thing. </p>
  
  <p>scripts: </p>
  
  <pre><code>$pip install virtualenv  
  $cd /d d:
  $mkdir test
  $cd test
  $virtualenv  flaskEnv
  $cd flaskEnv/Scritps/
  $activate
  $cd ../../
  $pip install flask
  </code></pre>
  
  <p>log file as below:</p>
  
  <pre><code>Collecting flask
    Using cached Flask-0.11.1-py2.py3-none-any.whl
  Requirement already satisfied (use --upgrade to upgrade): click&gt;=2.0 in c:\projects\flask-react\flsk\lib\site-packages (from flask)
  Requirement already satisfied (use --upgrade to upgrade): Werkzeug&gt;=0.7 in c:\projects\flask-react\flsk\lib\site-packages (from flask)
  Collecting Jinja2&gt;=2.4 (from flask)
    Using cached Jinja2-2.8-py2.py3-none-any.whl
  Collecting itsdangerous&gt;=0.21 (from flask)
  Collecting MarkupSafe (from Jinja2&gt;=2.4-&gt;flask)
    Using cached MarkupSafe-0.23.tar.gz
  Building wheels for collected packages: MarkupSafe
    Running setup.py bdist_wheel for MarkupSafe: started
    Running setup.py bdist_wheel for MarkupSafe: finished with status 'error'
    Complete output from command c:\projects\flask-react\flsk\scripts\python.exe -u -c "import setuptools, tokenize;__file__='c:\\users\\admini~1\\appdata\\local\\temp\\pip-build-3ep417\\MarkupSafe\\setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" bdist_wheel -d c:\users\admini~1\appdata\local\temp\tmp8mkr70pip-wheel- --python-tag cp27:
    running bdist_wheel
    running build
    running build_py
    creating build
    creating build\lib.win32-2.7
    creating build\lib.win32-2.7\markupsafe
    copying markupsafe\tests.py -&gt; build\lib.win32-2.7\markupsafe
    copying markupsafe\_compat.py -&gt; build\lib.win32-2.7\markupsafe
    copying markupsafe\_constants.py -&gt; build\lib.win32-2.7\markupsafe
    copying markupsafe\_native.py -&gt; build\lib.win32-2.7\markupsafe
    copying markupsafe\__init__.py -&gt; build\lib.win32-2.7\markupsafe
    running egg_info
    writing MarkupSafe.egg-info\PKG-INFO
    writing top-level names to MarkupSafe.egg-info\top_level.txt
    writing dependency_links to MarkupSafe.egg-info\dependency_links.txt
    warning: manifest_maker: standard file '-c' not found
  
    reading manifest file 'MarkupSafe.egg-info\SOURCES.txt'
    reading manifest template 'MANIFEST.in'
    writing manifest file 'MarkupSafe.egg-info\SOURCES.txt'
    copying markupsafe\_speedups.c -&gt; build\lib.win32-2.7\markupsafe
    running build_ext
    building 'markupsafe._speedups' extension
    error: [Error 2] The system cannot find the file specified
  
    ----------------------------------------
    Running setup.py clean for MarkupSafe
  Failed to build MarkupSafe
  Installing collected packages: MarkupSafe, Jinja2, itsdangerous, flask
    Running setup.py install for MarkupSafe: started
      Running setup.py install for MarkupSafe: finished with status 'error'
      Complete output from command c:\projects\flask-react\flsk\scripts\python.exe -u -c "import setuptools, tokenize;__file__='c:\\users\\admini~1\\appdata\\local\\temp\\pip-build-3ep417\\MarkupSafe\\setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record c:\users\admini~1\appdata\local\temp\pip-8v3_ep-record\install-record.txt --single-version-externally-managed --compile --install-headers c:\projects\flask-react\flsk\include\site\python2.7\MarkupSafe:
      running install
      running build
      running build_py
      creating build
      creating build\lib.win32-2.7
      creating build\lib.win32-2.7\markupsafe
      copying markupsafe\tests.py -&gt; build\lib.win32-2.7\markupsafe
      copying markupsafe\_compat.py -&gt; build\lib.win32-2.7\markupsafe
      copying markupsafe\_constants.py -&gt; build\lib.win32-2.7\markupsafe
      copying markupsafe\_native.py -&gt; build\lib.win32-2.7\markupsafe
      copying markupsafe\__init__.py -&gt; build\lib.win32-2.7\markupsafe
      running egg_info
      writing MarkupSafe.egg-info\PKG-INFO
      writing top-level names to MarkupSafe.egg-info\top_level.txt
      writing dependency_links to MarkupSafe.egg-info\dependency_links.txt
      warning: manifest_maker: standard file '-c' not found
  
      reading manifest file 'MarkupSafe.egg-info\SOURCES.txt'
      reading manifest template 'MANIFEST.in'
      writing manifest file 'MarkupSafe.egg-info\SOURCES.txt'
      copying markupsafe\_speedups.c -&gt; build\lib.win32-2.7\markupsafe
      running build_ext
      building 'markupsafe._speedups' extension
      error: [Error 2] The system cannot find the file specified
  </code></pre>
  
  <p>Does the error message mean something to anyone?
  thanks</p>