* Peter Tanski:
Quite right; my mistake: under the OpenSSL license a developer cannot mention features of the software in advertising materials, so the license grant of the GPL-OpenSSL program to the developer is void. The reason I mentioned "users" only was that in the particular problem we have here GHC does not use any other GPL programs (I think I am correct--readline is the unix version, not the GPL version, correct?)
On most systems, readline is GPLed. There is a non-copyleft reimplementation somewhere, but I don't think it's widely used.
The advertising requirement in the OpenSSL license would certainly constitute a "further restriction" under GPLv2 section 6; the strange implication is that the "no further restriction" clause is so broad
It has to be very broad, otherwise developers could bypass the copyleft concept.
the same clause (verbatim) in section 10 of the LGPL means the GPL license is incompatible with the terms of the LGPL!
The LGPL permits relicensing of covered works under the GPL. Without that provision, it would indeed be incompatible with the GPL.