Combining GPL and non-GPL code

[Rick Moen]

Quoting John Cowan (cowan at ccil.org):

> Quite so.  But the copyright on a derivative work (as opposed to a mere
> collective work) belongs to the deriver, provided the derivation was
> lawfully made, which means obeying any licensing requirements attached
> to the original.  So this is not "relicensing" or "sublicensing", it's
> applying the license permissions to make a derivative work.

Sure, I'll go along with that.  The work entailed in creating the
derivative (the set of incremental changes), to the extent it gives rise
to copyright title, is required to be available under GPL terms in order
to qualify for creation and distribution of that derivative, rights
otherwise reserved.

If anyone wants access to the BSD-licensed code in your hypothetical
under its owner's terms, that access does remain available -- anywhere
such separate code can be found.

Note:  It might be argued that the changes required to Exim to hack in
OpenSSL calls raise derivative work questions, as opposed to merely
creating a collection.  When my friend Marc Merlin wrote the bridge code 
patches in around 2000, arguably they used significant copyrightable
elements of OpenSSL, as GNU TLS wasn't yet available.  (At that time,
Phil Hazel had Exim under pure GPLv2:  Marc released the patched Exim
tarball, I pointed out the licensing problem, Marc swore a blue streak,
and an e-mail to Phil resulted in him amiably issuing the needed licence
exception.)