title: How to tell VSCode where to find header and source files
body: <p>I have a complex directory structure for a C project in which CMAKE governs which files are used for a certain project.</p>
  <p>I tried using CMAKE extensions for VSCode, but it did not work very well.</p>
  <p>Is there a way to tell VSCode which files exactly are used to be able to navigate through the code?</p>