Added new add_os method
Added new add_os method

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