[bug#33059] [PATCH 01/10] gnu: Add python-mpi4py.

[Paul Garlick <pgarlick@tourbillion-technology.com>]

Hi Eric,

> Would this package be better
> put in (gnu packages mpi).  Same with the petsc4py and slepc4py, in
> (gnu packages maths).

Yes, good idea.  These three dependencies are 'external', in the sense
that their development is independent of the FEniCS project.  They
could be used as dependencies of future packages that may not go in
(gnu packages simulation).

Also, the versions of petsc4py and slepc4py keep track of petsc and
slepc.  So version 3.9.1 of petsc4py, for example, depends on version
3.9 of petsc.  Keeping the package definitions near to each other in
the same module will be a useful 'aide memoire'.

I shall wait a little longer for any more comments, then move these
three definitions in the way you suggest and re-submit as 'v2'.
patches.

Best regards,

Paul.