Note the "(at your option) any later version" clause.

The COPYING file contains this:

   *     GNU LESSER GENERAL PUBLIC LICENSE
   *          Version 2.1, February 1999
   * [This is the first released version of the Lesser GPL.  It also counts
   *  as the successor of the GNU Library Public License, version 2, hence
   *  the version number 2.1.]

It seems to me that code is licensed under LGPL 2.1, as was mentioned by the cheat-engine author in the github issues.

Edit: Fabrice Bellard is also the author of libtcc, who has chosen to release that project under LGPL, so this is irrelevant to begin with. The file is LGPL.

The copying file was added years later and not by the same author as the original license. It looks like tcclib itself messed up somewhere along the lines here.

Also, "any later version" is any later version of the same license. LGPL and GPL are two separate licenses- you can't switch GPL to LGPL using this clause.

GNU Library Public License (LPL?) != GNU General Public License (GPL)

"Lesser General Public License"

I assume that it used to stand for "library", and this was changed to discourage people from thinking of this library as the default license for libraries, and consider using the GPL instead. For example, the GNU Readline library is GPL, and this is reportedly the reason why CLISP is also GPL'd.

Yes, but GP was suggesting that the GNU LGPL 2.1 was a possible successor license to the GPL 2, based on the quote in the LGPL 2.1 text that says

> [This is the first released version of the Lesser GPL. It also counts as the successor of the GNU Library Public License, version 2, hence the version number 2.1.]

If, as the parent comment claims, the library has been relicensed more permissively then it is irrelevant that it was previously only licensed under the GPL. Though it is certainly bad form to continue distributing it with that notice.

There's a bit of a myth that if you release a program containing GPLed code then you irrevocably get the obligation to release your source code whether you want to or not. Certainly you're in violation of the terms if you don't, but releasing your source code is not the only way to correct the violation. Even if you were successfully taken to court over the matter (which can only be done by the copyright owner of the GPLed software, since it's a contract with them that you're breaching), the court might require another resolution e.g. that you remove the GPLed code from your software or pay the copyright owner a fee/fine.

The “relicensing” file, found higher in the directory tree, expresses Fabrice Bellard’s intent to relicense his tcc contributions under an MIT-style license. So that file is available for use under multiple licenses, even if it only explicitly mentions the GPL in the comments.

https://github.com/cheat-engine/cheat-engine/blob/master/Che...

This! Great find. The project owners should add a comment to the top of file "Cheat Engine/tcclib/il-opcodes.h" with a reference to this relicensing agreement.