Whipped up some demo code for a proof of concept I needed. Used FPDM which states as its license "FPDF". The FPDF license seems Free to me -
Permission is hereby granted, free of charge, to any person obtaining a copy of this software to use, copy, modify, distribute, sublicense, and/or sell copies of the software, and to permit persons to whom the software is furnished to do so.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED.
I needed to fix a few things in FPDM. Can I distribute my code, and the changed version of FPDM under the GPLv2 ?
If no, can I distribute the fixed version of FPDM under the same "FPDF license" I obtained it under, and my own original code that calls it as GPLv2 ?
If no to all of this, what license can I use that ensures anyone else with a copy of my work is able to use it permissively? I prefer the GPLv2 for reasons... and the code is PHP, so it is "open" if not Free.