title: Add only non-whitespace changes
body: <p>I have my text editor to automatically trim trailing whitespace upon saving a file, and I am contributing to an open source project that has severe problems with trailing whitespace.</p>
  
  <p>Every time I try to submit a patch I must first ignore all whitespace-only changes by hand, to choose only the relevant information. Not only that, but when I run <code>git rebase</code> I usually run into several problems because of them.</p>
  
  <p>As such I would like to be able to add to index only non-whitespace changes, in a way similar that <code>git add -p</code> does, but without having to pick all the changes myself.</p>
  
  <p>Does anyone know how to do this?</p>
  
  <p>EDIT: I <strong>cannot</strong> change the way the project works, and they have decided, after discussing it on the mailing list, to ignore this.</p>