Re: What if Guile changed its license to be LGPL?

[Marius Vollmer]

Per Bothner <address@hidden> writes:

> Marius Vollmer wrote:
> > The special license of Guile means that we can't use other LGPLed
> > software for it without putting the whole of Guile under the LGPL,
> > effectively.
> 
> I don't believe that is the case.  There is no conflict between
> the LGPL and the Guile GPL+exception license.

No, there is no conflict, but unconditionally linking libguile to
libgmp would mean that all users of libguile would also have to obey
the license terms of libgmp.

We wouldn't need to change the license of Guile to the LGPL, but if
Guile's license would be effectively the LGPL, there would be little
point of keeping the current, 'non-standard' license.

> [...] For most people this is not an issue: They can link against a
> shared library version of libgmp.  (I see that Red Hat 7.3 comes
> with such a shared library.)  The main problem is for people on
> embedded systems.  They are unlikely to be using Guile, or if they
> use Guile, they are unlikely to want bignums.
> 
> So I don't think it's a real problem.  My suggestion:
> (1) Keep the Guile license as is.
> (2) Add a --with-gmp configure option.  It defaults to true if
> it finds a shared library version of libgmp; false otherwise.

I would like to make it fail when no libgmp can be found (shared or
non-shared) so that people don't accidentally build a inferior Guile
but take it for the real stuff and are disappointed.

> You might (if you haven't already) ask RMS about modifying the GMP
> license to GPL+exception, at least in the context of Guile.

I haven't asked, and I don't really like to go that route.  I
(personally) don't want to weaken the license of other peoples
software.

> (I would also love to be able to use GMP for libgcj, the GCJ Java
> run-time library, when implementing java.lang.math.)

What about creating a library that is reasonably compatible to GMP but
is simple minded and comes with a very unrestrictive license.  It's
sole purpose would be to make use of the permissive license of
libguile (and of libgcj, if I understand your intention right).

This will work, but it certainly feels quite strange to me to provide
a tool to eclipse GNU MP from within the GNU project itself.