Bug#765354: llvm-defaults: lldb: fix FTBFS on ppc64el/arm64 (patch)

[peter green]

Thanks for fixing llvm-defaults on arm64 and ppc64el. Could you file an 
unblock release with the release team so we can get it fixed in testing?

I could do it myself but I don't feel competant to be in the middle of 
any resulting discussion about the specifics of llvm packaging so I 
think it's better if it comes from the maintainer.