General Polygon Clipper, aka GPC, version 2.33
See GPC-README.pdf for more official information about this library.
GPC was discontinued in August of 2020 with the following note on the website:
As of August 2020, GPC is no longer distributed or available.
This begged the questions of, how do you get GPC? And, what is the licensing now?
On Twitter, we were able to get ahold of Toby Howard who had this to say:
I was the licensing manager for GPC. In 2020 the author of the software decided to withdraw its official distribution. If you obtain a copy of GPC from another source you can use it without any licensing requirement. I've updated Wikipedia to clarify. Hope this helps.
I'm therefore placing this onto GitHub under the MIT License. If Alan Murta, Toby Howard, or the University of Manchester would like me to remove it or make other changes, just ask and I'll respect your wishes. I can be contacted on Twitter at https://twitter.com/rickbrewPDN.