Supporting LLVM 3.5 and 3.6

[Rainer Schuetze via digitalmars-d-ldc]

On 14.07.2017 14:42, David Nadlinger via digitalmars-d-ldc wrote:
> I was going to suggest culling < 3.7 support as well.
> 
> I'm still toying with the idea of going with a vendored LLVM so we can 
> more efficiently support work like Android, SPIR-V, etc., but for now I 
> guess there isn't really a reason to throw a wrench into the distro 
> packaging process.

That could also help getting a D specific language identifier into 
CodeView debug information to support mago with the VS Concord debug 
engine.

I just filed a bug report against LLVM 
(https://bugs.llvm.org/show_bug.cgi?id=33899) to have this added to 
master, but it won't help for releases build against older LLVM versions.