title: Scripting: insert an additional #include after the last #include in many, many files
body: <p>For a second I was hoping to get away with <code>sed</code>'s <code>a\</code> command, but <code>sed</code> (in my hands, anyway) isn't really a fan of keeping state (inserts after every #include).</p>
  
  <p>So is there a way to do this with <code>sed</code>? Is there a <em>smart</em> way of doing this?</p>
  
  <p>I'll resort to writing a regular Python/Ruby script if that's the way to go, but this seems to be a problem someone has probably bumped into somewhere, sometime.</p>