I noticed the following code in vgl, which appears to restrict vgl from commercial use. I believe it must be removed unless we receive unrestricted permission from the University of Manchester.
Project: Generic Polygon Clipper
A new algorithm for calculating the difference, intersection,
exclusive-or or union of arbitrary polygon sets.
Author: Alan Murta (email: firstname.lastname@example.org)
Date: 17th December 2004
Copyright: (C) 1997-2004, Advanced Interfaces Group,
University of Manchester.
This software is free for non-commercial use. It may be copied,
modified, and redistributed provided that this copyright notice
is preserved on all copies. The intellectual property rights of
the algorithms used reside with the University of Manchester
Advanced Interfaces Group.
You may not use this software, in whole or in part, in support
of any commercial product without the express consent of the
There is no warranty or other guarantee of fitness of this
software for any purpose. It is provided solely "as is".