title: Building Boost.Build engine 'cl' is not recognized as an internal or external command, operable program or batch file
body: <p>Can someone tell me why bootstrap.bat failed?</p>
  
  <p>Platform:<br>
  Windows 10<br>
  Boost boost_1_63_0</p>
  
  <pre><code>C:\Boost\boost_1_63_0&gt;bootstrap.bat
  Building Boost.Build engine
  'cl' is not recognized as an internal or external command,
  operable program or batch file.
  
  Failed to build Boost.Build engine.
  Please consult bootstrap.log for further diagnostics.
  
  You can try to obtain a prebuilt binary from
  
     http://sf.net/project/showfiles.php?group_id=7586&amp;package_id=72941
  
  Also, you can file an issue at http://svn.boost.org
  Please attach bootstrap.log in that case.
  
  C:\Boost\boost_1_63_0&gt;
  </code></pre>