petsc : added variants and logic to build various flavors
petsc : added variants and logic to build various flavors

krafczyk/spack,tmerrick1/spack,EmreAtes/spack,LLNL/spack,lgarren/spack,iulian787/spack,iulian787/spack,matthiasdiener/spack,lgarren/spack,skosukhin/spack,iulian787/spack,tmerrick1/spack,skosukhin/spack,TheTimmy/spack,TheTimmy/spack,tmerrick1/spack,EmreAtes/spack,mfherbst/spack,LLNL/spack,krafczyk/spack,skosukhin/spack,EmreAtes/spack,matthiasdiener/spack,mfherbst/spack,mfherbst/spack,skosukhin/spack,iulian787/spack,tmerrick1/spack,iulian787/spack,EmreAtes/spack,tmerrick1/spack,matthiasdiener/spack,mfherbst/spack,lgarren/spack,krafczyk/spack,skosukhin/spack,lgarren/spack,EmreAtes/spack,matthiasdiener/spack,lgarren/spack,matthiasdiener/spack,krafczyk/spack,krafczyk/spack,TheTimmy/spack,LLNL/spack,LLNL/spack,TheTimmy/spack,TheTimmy/spack,mfherbst/spack,LLNL/spack