GCC : removed dependency on libelf. Removed isl variant
GCC : removed dependency on libelf. Removed isl variant

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