Build PyMFEM against Spack MFEM install

[mdavids-cfs]

Hi all,
I was wondering if it's possible to install PyMFEM against a Spack install of MFEM?
The current setup.py works pretty well for a basic build version (MPI, Hypre, METIS) but I think it would be fantastic too add a more flexible/adjustable way of installing building PyMFEM. One specific example that drove me to install MFEM using Spack (rather than a lot of manual fun with cmake) was difficulty building MFEM with MUMPS (which needs a fortran compiler), and Spack handled that really well.

So, I guess, the question would be:

1. Is it possible to build against a Spack install, and if so is there any guidelines somewhere on this repo?
2. If this is not possible yet, would it be worth considering?

If you say it's possible but not currently supported I may be able to take a shot at that, but wanted to hear your thoughts, if there is significant barriers to making this happen.

Thanks a bunch!
Mathias

PS: This is somewhat related to #36