title: Call CMake from python script results in "Could not create named generator"
body: <p>I'm building a project that should be able to move freely between machines. In order to not have hundreds of MB of libs I'm writing a series of python scripts that download and build the dependencies as well as my own project. I'm using CMake to generate VS projects.</p>
  
  <p>To call CMake I build a command line and I use python <code>subprocess.check_call</code> as below</p>
  
  <pre><code>cmakeCmd = ["cmake.exe", '-G "Visual Studio 11 Win64"', build_path]
  retCode = subprocess.check_call(cmakeCmd, stderr=subprocess.STDOUT, shell=True)
  </code></pre>
  
  <p>The problem is that if I use <code>-G</code> option from CMake I get the following error regardless of the generator I choose:</p>
  
  <pre><code>CMake Error: Could not create named generator  "Visual Studio 11 Win64"
  </code></pre>
  
  <p>I was thinking that should be some enviroment variable missing but the python path is complete with all my systems' variables.</p>
  
  <p>What is odd is that if I don't set the generator and let CMake choose the default one the script runs fine. I have no ideia why.</p>