title: How to have CMake show headers-that are not part of any binary target-in the IDE?
body: <p>In our workflow, we can have a <em>module A</em> that is composed of several header files, <em>module A</em> not producing any binary (side note: it will obviously be used by other modules, that include some of the headers from <em>module A</em> to produce binaries).</p>
  
  <p>A good example would be a header-only library, for which CMake 3 introduces a good support thanks to the notion of <code>INTERFACE</code> library (see <a href="https://stackoverflow.com/a/11583676/1027706">this SO answer</a>, and CMake's <a href="http://www.cmake.org/cmake/help/v3.0/manual/cmake-buildsystem.7.html#interface-libraries" rel="noreferrer">documentation of the feature</a>).</p>
  
  <p>We can make an interface library target out of <em>module A</em>:</p>
  
  <pre><code>add_library(module_A INTERFACE)
  </code></pre>
  
  <p>That gives us all the nice features of CMakes targets (it is possible to use it as another target's dependency, to export it, to transitively forward requirements etc.)</p>
  
  <p>But in this case, the headers in <em>module A</em> do not show up in our IDE (Xcode, yet we expect it to be the same with most/every other IDE).</p>
  
  <p>This proves to be a major drawback in the workflow, since we need the files composing <em>module A</em> to be shown in the IDE for edition. Is it possible to achieve that ?</p>