title: Visual Studio C++ add standard header location only with environment variable
body: <p>I have an external dependency in my project which I can't change. It is built with some very complex Python which calls some more build tools.</p>
  
  <p>This all eventually boils down to compile error: the C++ just cant find a header file.</p>
  
  <p>The header file is included like this: </p>
  
  <pre><code>#include &lt;sqlite3.h&gt;
  </code></pre>
  
  <p><strong>The question:</strong></p>
  
  <p>Is it possible to add a custom include directory to Visual Studio C++ with the help of just environment variables. And if it is - how?</p>
  
  <p>I can't change the solution nor project nor source files - they all are being download automatically</p>
  
  <p>I'm using most recent visual studio - 2017</p>