title: Add a copyright notice to all files in a directory using Ant
body: <p>I want to add a copyright notice to a series of files generated in an Ant build. What's the easiest way to do it?</p>
  
  <p>I thought about using <code>&lt;concat&gt;</code> but I don't understand how to run it on a fileset without concatenating all the files in the fileset.</p>
  
  <p>Thanks!</p>