[MUMPS] Various improvements in the package.
[MUMPS] Various improvements in the package.

* Fix a bug when checking for 'xl' or 'xl_r' compiler.
* Add support for parallel build - the 's', 'c', 'd', and 'z' targets
  are build separately allowing parallel builds.
* When build '+shared', inject all dependencies into the link lines of
  the mumps libraries.
* Run the examples only when installing with the '--test' Spack option.

krafczyk/spack,tmerrick1/spack,mfherbst/spack,tmerrick1/spack,EmreAtes/spack,LLNL/spack,matthiasdiener/spack,krafczyk/spack,LLNL/spack,mfherbst/spack,matthiasdiener/spack,mfherbst/spack,tmerrick1/spack,krafczyk/spack,iulian787/spack,krafczyk/spack,EmreAtes/spack,EmreAtes/spack,matthiasdiener/spack,krafczyk/spack,mfherbst/spack,matthiasdiener/spack,iulian787/spack,matthiasdiener/spack,iulian787/spack,LLNL/spack,EmreAtes/spack,tmerrick1/spack,iulian787/spack,EmreAtes/spack,LLNL/spack,mfherbst/spack,LLNL/spack,tmerrick1/spack,iulian787/spack