- update to newer mpich
- find new compilers automatically, and display them
- force use of gcc 7.x

- likely will tweak arguments later

- current one doesn't seem to build on Bebop for some reason

- was launching worker threads on main pool instead of explicitly
created pool with multiple ES's

- also update yaml to build fewer spack packages

- also rename some scripts and email headings for consistency

- requires 'udreg' memory registration method
- works with libfabric 1.7
- use patches for now until changes upstreamed
- packages.yaml tweaked to reduce build time

- passed directly to margo_init, creates dedicated ES's to use for RPC
  handling, which in turn causes more pmdk operations to be issued
  concurrently

- set LD_LIBRARY_PATH more broadly to avoid library not found problems
- force placement to specific nodes to match target location
- concurrent job crashing for unknown reasons at this point

- fall back to using LIBRARY_PATH to populate LD_LIBRARY_PATH
  (still not clear why rpath doesn't work)
- don't build custom uuid library

- need to find correct solution later; this is a hack