Curl: LGPL m4/ax_code_coverage.m4 conflicts with ISC license of curl source package

[wrowe]

The file m4/ax_code_coverage.m4 was introduced to Curl two years ago;
https://github.com/curl/curl/commit/f6e0f4556eabc8c2629d16ae599a153392d30d05
and distributed in source bundles since 7.54.1. It is incorporated into
the project's ./configure script as part of the automake/autoconf
preparation. This renders the source code package contents including
generated ./configure incompatible with the ISC license from COPYING,
as portions of ./configure are then under LGPL 2.1 terms. The terms of
m4/ax_code_coverage.m4 license further place the burden on Curl to
share the LGPL 2.1 document when distributing this macro.

This macro, as opposed to most autoconf/automake macros, failed
to offer the following licensing exception which is used to make usable
automake and autoconf for ISC, BSD and similarly licensed works;

~~~

As a special exception, the respective Autoconf Macro's copyright owner

gives unlimited permission to copy, distribute and modify the configure

scripts that are the output of Autoconf when processing the Macro. You

need not follow the terms of the GNU General Public License when using

or distributing such scripts, even though portions of the text of the

Macro appear in them. The GNU General Public License (GPL) does govern

all other use of the material that constitutes the Autoconf Macro.

~~~

I have confirmed the current sources contain the same defect;
http://git.savannah.gnu.org/gitweb/?p=autoconf-archive.git;a=blob_plain;f=m4/ax_code_coverage.m4
If the 6 authors agreed on adding the clause, they could elect to relicense.
In the interim, I believe the patch needs to be reverted.

[bagder]

I agree with the conclusions and as a consequence I'm doing a rewrite and simplification of that logic to remove the dependency without losing functionality.

[bagder]

Thanks for the report. Issued fixed!