Why the commercial license for pngquant? Maybe rewriting pngcrush IP and slapping a commercial license on it is copyright infringement. This is my impression of Rust. Take others IP, rewrite it in Rust, poof copyright magically transferred. The C99 version how much of that is from prior art?
Lets just ignore prior art and associated license terms
written by Kornel Lesiński
ImageOptim Ltd. registered in England and Wales under company number 10288649 whose registered office is at International House, 142 Cromwell Road, London, England, SW7 4EF
First commit Sep 17th, 2009
Copyright (C) 1998-2002, 2006-2016 Glenn Randers-Pehrson
glennrp at users.sf.net
Portions copyright (C) 2005 Greg Roelofs