relicense some modules for use under GPLv2+

[Bruno Haible]

Hi,

Often gnulib has relicensed modules for use in LGPLv2+ packages (such as
libvirt).

Some modules have also be relicensed for use in "dual LGPLv3+ or GPLv2"
packages (such as GNU libunistring). [1]

Today, I would like to ask for relicensing of specific modules for use in
GPLv2+ programs, namely GNU clisp.

GNU clisp is under GPLv2+, not GPLv3+, because it was designed, from the
beginning, as a vehicle for running computer algebra systems. The most
prominent computer algebra system written in Lisp is Maxima, and is under
GPLv2. If clisp was only distributed under GPLv3+, one could no longer
distribute maxima with/in clisp.

So, regarding gnulib, I'd like

1) to introduce an option --gpl=v2+ that, like the --lgpl option, verifies
   license compatibility and updates the copyright header in the source
   files,

2) ask for relicensing LGPL -> 'LGPLv3+ or GPLv2' of the modules
     no-c++
     mkfifo
     mknod
     strftime, nstrftime, time_rz, tzset

3) ask for relicensing GPL -> GPLv2+ of the modules
     c-strtod
     getloadavg
     link-follow
     libsigsegv
     vma-iter

Thoughts?

Can we go ahead, as usual, with per-module approval by the authors of said
modules?

Bruno

[1] https://lists.gnu.org/archive/html/bug-gnulib/2016-11/msg00036.html