> Okay, so changing a license to GPL does not violate the conditions of the BSD. You just have to maintain the little notice and the copyright.
Not requiring this downstream violates the BSDL, but requiring it downstream, violates the GPL, at least in GPLv2, which does not itself require it, and prohibits additional terms to its own.
I think the GPLv3's allowance of additional terms is broad enough to actually make some of the licenses that the FSF promoted as GPL compatible under GPLv2 but which were clearly not on a reasonable reading of the terms of the licenses compatible with the GPLv3.
Not requiring this downstream violates the BSDL, but requiring it downstream, violates the GPL, at least in GPLv2, which does not itself require it, and prohibits additional terms to its own.
I think the GPLv3's allowance of additional terms is broad enough to actually make some of the licenses that the FSF promoted as GPL compatible under GPLv2 but which were clearly not on a reasonable reading of the terms of the licenses compatible with the GPLv3.