Use MPICH scripts to generate stuff

[jeffhammond]

I think I can use the LLNL wrap generator for Fortran, with some hacking.

[jeffhammond]

Do this with MPICH scripts instead. @dalcinl knows how to do it.

[dalcinl]

Please be aware that MPICH scripts are not really a general purpose tool. Any attempt to retarget them to generate stuff outside of MPICH needs may require heavy editing. For example, the Fortran stuff that you saw me produce and that we eventually decided to kill took quite a bit of work on my side.

[dalcinl]

Maybe https://github.com/mpi-forum/pympistandard would be a more appropriate thing to base code generation on.

[jeffhammond]

I'll use whatever works. The stuff you used to generate the ill-fated stubs would be really useful.