Re: GPL and XML
*bzzt* wrong. Looking at GPLv2 (applicable in this case)
1. You may copy and distribute verbatim copies of the Program's source code as you receive it
OK, that's what's being done. As long as the license is included.
2. You may modify your copy or copies of the Program or any portion of it, thus forming a work based on the Program... required to locence under GPL
There's no modification, it's being distributed as is. So the viral part doesn't apply.
Sorry, including a GPL'd file is fine, and doesn't require the rest of your project be GPL'd.