freeness and compatibility of CeCILL-C licence

[Drew Parsons <dparsons@debian.org>]

There are various discussions about the status of the CeCILL-C licence
v1 (and other CeCILL licences) in the history of this mailing list. 
It's not listed at https://www.debian.org/legal/licenses/
but when it last came up on this list, Thibaut Paumard suggested it's
fine, LGPL compatible, 
https://lists.debian.org/debian-legal/2010/01/msg00064.html
Is this still the consensus?

The French scientific computing community have been been quite active,
with many packages released under CeCILL licences. If CeCILL-C is an
acceptable licence, should it (and the other CeCILLs) be added to 
https://www.debian.org/legal/licenses/ ?

CeCILL-C v1 itself is http://www.cecill.info/licences/Licence_CeCILL-C_V1-en.html

My interest is in MUMPS, http://mumps.enseeiht.fr/
whose latest version is licensed CeCILL-C v1.

Thanks,
Drew