RHEL 6.6 MPI mess

[Dave Love]

The undocumented openmpi and mpich updates in RHEL6.6 have broken binary
compatibility and seem to be provoking general rebuilds of things in
EPEL.  While that may be OK for things that are packaged in EPEL, it at
best doesn't help with our HPC users' locally-built programs or
local/copr-published rpms (especially if the rebuilds involve their own
ABIs incompatibilities, like scalapack currently in testing).

It seems to me that the best approach, assuming Red Hat won't address
the issue, is to supply compatibility packages in EPEL if that will
work.  I haven't had a chance to try, but I'll probably have to make
something work eventually for openmpi, and presumably there are plenty
of people in a similar situation.  The updates are blocked by the
dependencies of many installed packages here, but it will be
increasingly awkward with packages that can't be updated without
rebuilds.

Has anyone tried that tack already, or is it clear it can't work for
some reason?