title: How to diff just the source files?
body: <p>I have two almost similar source code trees, but do not have access to the source code repository so I am stuck with release packages that contain also test reports, documentation, binaries etc.</p>
  
  <p>the <code>diff</code> command only support <code>--exclude</code>, but I would like to do something like <code>diff -wbur --include='*.c,*.h' tree1 tree2</code></p>
  
  <p>I know that <a href="https://stackoverflow.com/questions/483849/how-do-you-use-the-diff-command-against-two-source-trees">this question</a> is somewhat related, but does not really address my issue.</p>
  
  <p>Bonus points for ignoring change blocks that are completely in C comments :)</p>