Licensing issue with Gmsh?

[zimoun]

Dear,

I am updating the package gmsh.  Currently, the part ’contrib/metis’ is
removed with the comment “non-free METIS code”:

--8<---------------cut here---------------start------------->8---
      (snippet
       ;; Remove non-free METIS code
       '(begin
          (delete-file-recursively "contrib/metis")
          #t))))
--8<---------------cut here---------------end--------------->8---

However, METIS is licensed Apache v2.0 and note that there is one
package ’metis’ (“guix show metis”) but it cannot be used, anyway.


The code is here:

  <https://gitlab.onelab.info/gmsh/gmsh/-/tree/master/contrib/metis>

What is wrong with the licensing?  Only the header of files?


Note that Debian compiles it with METIS: 

<https://salsa.debian.org/science-team/gmsh/-/blob/master/debian/rules#L37>

Nnot checked with other distributions.)


I am inclined to enable METIS because it appears to me fine.  However,
since freedom is essential, it would like another advice and/or comment
on.

Thank you in advance.

All the best,
simon

ps:
I discussed this point upstream:
<https://gitlab.onelab.info/gmsh/gmsh/-/issues/1013>