Since the SPL will be relicensed under the CDDL in the future, it might be a good idea to dual-license this header. I am not a lawyer, but I imagine that would look something like this:

```
Copyright © 2013, DHE. All rights reserved.

The contents of this file are subject to the terms of either the GNU
General Public License Version 2 only ("GPL") or the Common
Development and Distribution License("CDDL") (collectively, the
"License"). You may not use this file except in compliance with the
License. You can obtain a copy of the Licenses at
http://opensource.org/licenses/gpl-2.0.php
http://opensource.org/licenses/cddl1.php
```