title: CLion indexer does not resolve some includes in the project directory
body: <p>I have a CLion C++ project that has the following structure:</p>
  
  <pre><code>    project
         ----&gt;my_includes
         |   ----&gt; my_own.hpp
         ----&gt;source
             ----&gt; my_app
                 ----&gt; my_src.cpp
  </code></pre>
  
  <p>The first line of my_src.cpp is </p>
  
  <pre><code>#include "my_includes/my_own.hpp"
  </code></pre>
  
  <p>I use an external build system that requires this inclusion format. The problem is if I use a function in my source file defined in the included header, CLion says "Cannot find my_own.hpp" if I try to hover over the inclusion.</p>
  
  <p>I tried marking the include directory as containing Project Source or Headers but this didn't fix it. Any ideas?</p>