try to use add-apt-repository for the upstream llvm repo
try to use add-apt-repository for the upstream llvm repo

soenkehahn/stackage,stackbuilders/stackage,creichert/stackage,fpco/stackage,Shimuuar/stackage,fimad/stackage,ethercrow/stackage,lwm/stackage,mrkkrp/stackage,massysett/stackage,garetxe/stackage,athanclark/stackage,mstksg/stackage,Daniel-Diaz/stackage,clinty/stackage,alanz/stackage,spencerjanssen/stackage,wereHamster/stackage,jonschoning/stackage,simonmichael/stackage,ygale/stackage,asr/stackage,peti/stackage,michalkonecny/stackage,judah/stackage,int-index/stackage,iand675/stackage,phaazon/stackage,mgajda/stackage,GregorySchwartz/stackage,k0ral/stackage