metis: bugfix: make shared library build portable (#4489)
metis: bugfix: make shared library build portable (#4489)

Fixes #4488. When compiling metis as a shared library, the package
used the syntax `-rpath=`, followed by a path. This syntax is
non-portable, so replace it using Spack's compiler rpath argument
property.
mfherbst/spack,lgarren/spack,tmerrick1/spack,iulian787/spack,matthiasdiener/spack,skosukhin/spack,mfherbst/spack,lgarren/spack,lgarren/spack,krafczyk/spack,krafczyk/spack,EmreAtes/spack,tmerrick1/spack,EmreAtes/spack,krafczyk/spack,mfherbst/spack,iulian787/spack,LLNL/spack,tmerrick1/spack,TheTimmy/spack,EmreAtes/spack,skosukhin/spack,LLNL/spack,lgarren/spack,skosukhin/spack,tmerrick1/spack,mfherbst/spack,EmreAtes/spack,TheTimmy/spack,LLNL/spack,iulian787/spack,TheTimmy/spack,TheTimmy/spack,iulian787/spack,krafczyk/spack,matthiasdiener/spack,EmreAtes/spack,skosukhin/spack,LLNL/spack,TheTimmy/spack,lgarren/spack,iulian787/spack,krafczyk/spack,mfherbst/spack,matthiasdiener/spack,LLNL/spack,matthiasdiener/spack,matthiasdiener/spack,tmerrick1/spack,skosukhin/spack