title: CMake dependency on defined (preprocessor) header file
body: <p>I have a configuration file setup that defines the correct header files to include for certain components. Later I include that file via the preprocessor token. Unfortunately CMake's dependency scanner completely ignores the header file.</p>
  
  <p>Essentially it comes down to this:</p>
  
  <pre><code>#define HEADER_FILE "somefile.h"
  #include HEADER_FILE
  </code></pre>
  
  <p>CMake does not add <code>"somefile.h"</code> to the list of dependencies for this source file!</p>
  
  <p>How can I get CMake to recognize this dependency correctly?</p>
  
  <p><em>(I know that I can do #if 0 blocks and include all the files, but this either includes too many dependencides for other sources, or defeats the whole purpose in the first place -- depending on how you do it)</em></p>