title: How to add header files in setup.py so dependencies are observed when building the extensions?
body: <p>The question seems long, but it all comes down to how I can add header files to specific extension specification.</p>
  
  <p>The motivation is that if I change one of the header files, issuing</p>
  
  <p>python setup.py build</p>
  
  <p>should rebuild the extension even when none of the .c files are changed.</p>
  
  <p>I've tried to add the depending header files in "sources" keyword arg in the Extension constructor, but running the resulting setup.py generated errors complaining about unknown file extension ".h".</p>
  
  <p>Thanks!</p>