Rust broken again! (but differently this time)

[Tobias Nygren <tnn%NetBSD.org@localhost>]

Hi,

Rust is now sadly broken on aarch64 too (and probably all arches except
amd64?). The bootstrap binaries need libLLVM-8.so which came implicitly
from lang/llvm, which was just updated to version 9. So we have nothing
that provides libLLVM-8.so. I guess the bootstrap files have to be
updated. It's better if we can make it use the built-in llvm
so it doesn't rely on existence of pkgsrc libraries.

Kind regards,
-Tobias