Jerry James wrote:
The GPLv2 vs. GPLv3 issue looks to be a deal breaker, though. Drat.
I wonder if I can talk the bliss authors into releasing a GPLv2+ or
LGPLv2+ version. It's worth a try. So far I haven't been able to get
a response out of the nauty developer, so little chance of a license
change there.
Well, Polymake itself is GPLv2+ (and thus compatible with GPLv3 code), but
I'm not sure about the other stuff it links in. Especially cddlib and liblrs
are extremely vague about licensing, so it isn't really clear whether they
actually want to allow any version of the GPL, or version 2 or later, or
just version 2. In principle, if they just say "This software is under the
GPL." without specifying a version, the GPL says you can use any version. If
they just drop in the GPLv2 COPYING without saying anything, it's a more
complicated matter. And whether that's what upstream intends is a different
matter entirely. I wish each GPLed software would carry a valid header
saying "version N or, at your option, any later version". I hate GPLvN-only
licensing (no matter what N is; even if there's nothing newer than v3 now,
authors should still use v3+ to plan for the future!) and vague licensing
not clearly stating anything about the GPL version.
Kevin Kofler