Bug#919628: Apply Julia's LLVM patches

[M. Zhou]

Package: llvm-6.0-dev
Version: 1:6.0.1-9.2
X-Debbugs-CC: ginggs at debian.org

Dear LLVM maintainers,

Please check and apply Julia's LLVM patches to Debian's LLVM 6.0.1:

https://github.com/JuliaLang/julia/blob/master/deps/llvm.mk#L390-L432
https://github.com/JuliaLang/julia/tree/master/deps/patches

I don't quite understand what these patches are doing. So in order to
use upstream's LLVM patches, the most straightforward way is to
ship an embedded LLVM in Julia's source package.