RFC: proposed GPLv3 license exception draft

[Ralf Wildenhues]

[ cross-posted to several groups; please followup on the autoconf list ]

In order to complete the GNU Project's migration to GPLv3, every GNU
program that has exceptions to its license needs to have those
exceptions updated for GPLv3.  We've prepared draft text for an updated
version of the Autoconf exception, and we're interested in hearing your
feedback on it.

The primary purpose of this update is to have the exception build on top
of the framework for Additional Permissions that GPLv3 provides in
section 7.  We are not trying to change the exception's underlying
policy: we still want to allow people to distribute the normal output of
Autoconf under any license they want.  However, the new draft does try
to address new issues that have come up since the current GPLv2-based
exception was written.

The new exception grants people permission to distribute Eligible Output
Material under terms of their choice.  In short, Eligible Output
Material is a more formally defined way of talking about the "configure
scripts" that are the subject of the old GPLv2-based exception.  One
change of note is that it is defined to explicitly exclude tracing
output, to prevent people from using that mechanism to be able to
distribute more source under the terms of the exception than they are
supposed to be able to.  If anyone causes Autoconf to output stuff that
is not Eligible Output Material, then they will not be able to take
advantage of the exception: they would have to distribute the configure
scripts under the terms of GPLv3 alone.

Another benefit of the new exception is that it is not FSF-specific in
any way.  When other copyright holders make modified versions of
Autoconf, they can apply the exact same permission text to their
changes, and it will work the way people want.

We hope that this new exception will help make Autoconf's licensing a
little more clear and robust -- if also a little more verbose -- in the
same way that GPLv3 has done for the entire free software community.  We
are interested in hearing feedback from Autoconf developers about
whether there might be intended good uses of the software that are not
covered by this exception -- or conversely, known bad uses of the
software that might be covered.  We're also interested in hearing if
there are particular parts of the text that you think might be
misunderstood by developers: it may not always be possible, but we'd
like for this exception to be as clear as possible to as many people as
possible.  If you're interested, please review the text and let us know
what you think.

Below is the text of the proposed exception.

Thanks to Brett Smith for help in preparing this message.

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This Exception is an additional permission under section 7 of the GNU
General Public License, version 3 ("GPLv3").

The purpose of this Exception is to allow distribution of Autoconf's
typical output under terms of the recipient's choice (including
proprietary).

0. Definitions

"Covered Code" is any source code and/or object code of Autoconf that is a
covered work under this License.

"Eligible Output Material" is Covered Code that is included in the
standard, minimally verbose, non-debugging and non-tracing output of the
version of Autoconf distributed to you under this License.  Moreover,
"Eligible Output Material" may be comprised only of Covered Code that (a)
must necessarily appear in Autoconf-generated configure scripts and (b) is
required for those configure scripts to function.

"Ineligible Output Material" is Covered Code that is not Eligible Output
Material.

1. Grant of Additional Permission.

You have permission to propagate output of Autoconf, even if such
propagation would otherwise violate the terms of GPLv3.  However, if you
cause Autoconf to output any Ineligible Output Material, you do not have
permission to convey the resulting covered work under this Exception and
you must remove this Exception in accordance with the second paragraph of
GPLv3's Section 7.

2. No Weakening of Autoconf Copyleft.

The availability of this Exception does not imply any general presumption
that third-party software is unaffected by the copyleft requirements of
the license of Autoconf.

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