Re: Linking clause deleted from GNAT GPL

[Glenn Maynard <glenn@zewt.org>]

On Mon, Nov 21, 2005 at 03:57:31PM +0100, Henning Makholm wrote:
> Scripsit Arnoud Engelfriet <galactus@stack.nl>
> 
> > Where is the statement that allows you to take off the linking
> > exception from the GNAT license?
> 
> It is not quite clear how the exception is to be interpreted. There
> are at least two possibilities:
> 
> 1) An ordinary GPL grant of rights is given. In _addition_ to that, the
>    licensor grants an additional right to distribute derivations in
>    certain circumstances where the GPL itself (by virtue of #2.b) does
>    not grant the right to distribute.
> 
> 2) The licensor grants a license which is as described by the text of
>    the GPL plus the exception, when interpreted under the peculiar
>    rule that whenever the GPL's text says "this License" it must be
>    construed as referring to the GPL+exception combination.
> 
> In case (1) AdaCore does have the right to distribute without the
> additional license. On the other hand, in case (2) "this License"
> in #2.b requires AdaCore to license their changes under the combined
> license.
> 
> The result of case (2) is that the combined license, while somewhat
> GPL-like is _not compatible with the unamended GPL_ in either
> direction. I would argue that it is unlikely that this is how the FSF
> really intended to license the code.

The only time I've actually seen an additional-permission clause that said
"you may remove this clause" to explicitly remain GPL-compatible was ones
drafted on this list, for linking to OpenSSL.  I agree that #1 is almost
certainly what was intended, but I don't know how to arrive from that from
the exception.

g++ headers include a clause like this (also not explicitly removable).
Most of gcc is under the plain GPL.  So, #2 would probably make these
pieces incompatible.

Since the copyright holder in this case is the FSF, it's probably best to
just ask them.  I'd be interested in their response on this, so if anyone
does, please get permission to repost their reply to the list.

-- 
Glenn Maynard