Comment # 19 on bug 1179155 from Richard Biener

Oh, and the best solution would be to drop 'llvm' (the meta package) from SLE
and only provide it via PackageHub.  We'd of course need to keep the "old"
'llvm' (in version 7) in the SLE build system or alternatively arrange all
packages that require llvm for building / running to use versioned requires
(and binaries).  Or divert all those packages to PackageHub as well.

Anyway, probably way too late now so forking of 'llvm' is the only realistic
plan.