Changing GPGME's license

[Ian Jackson]

Werner Koch writes ("Changing GPGME's license"):
> I recently had some discussion with Marcus and others, whether it
> might make sense to change the license of GPGME from the GPL to the
> LGPL.  Here are some thoughts:

Thanks for that illuminating message.  I've had some similar
conversations with a few people about adns.

I generally agree with your reasoning and can't help much with
deciding about what I see as the key tradeoff between different ways
of achieving different but important freedoms: ie, between the value
for freedom of the extra encouragement to make more software Free, and
the value for freedom of the extra deployment of user-controlled
cryptographic systems.

But I can comment somewhat on this question of yours:
> Therefore I think it is fair to ask for a financial compensation
> for a license change.

I agree that this can be a useful tactic.  But, there are issues with
trying to enforce such a thing so that the compensation doesn't turn
out to be a one-off, leaving the library LGPL forever.

What would be ideal would be a way to be able to say something like
`this is GPL, but as far as linking with program XYZ is concerned, it
can be treated as LGPL.'  Thus the licence change would apply only for
mixing with certain other applications.

As well as preventing the LGPLness from `leaking' into other programs,
and making the financial compensation an effective use of money for
the proprietary program with which you wish to allow mixing, this has
another useful effect: you can vary your compensation level according
to the project in question.  In particular, if the other project is
Free but not GPL-compatible, or very popular, or if there is some
reason for you to want very much to encourage them to use your
library, you can `gift' them the licence variation.

You'd probably want to think about the status of past and future
releases of your library wrt such a specific licence change.

I had a bit of a go at drafting such a limited licence change for
adns, but I stopped when the main enquirer who was asking turned out
not to be serious about the amount of money involved.

Ian.