llvm on ubuntu 18.04 LTS

[Gedare Bloom]

Hi Chris,

I'm trying out the rtems-llvm.bset on Ubuntu 18.04.

The first error I encountered was during cmake configuration for llvm,
it can't find swig.  So, I built the devel/swig.bset inside of bare,
and tried again. It got past that error, but it is picking up the
installed swig and not the swig that is built by the RSB.

I saw this in my rsb log. I'm not sure if it is important, but it
doesn't seem to affect anything:
-- Found Git: /usr/bin/git (found version "2.17.1")
-- git Version: v0.0.0
-- Version: 0.0.0

The second error I encountered comes from missing libedit_INCLUDE_DIRS
I had a few options, but I went with: apt-get install libedit-dev

This got me past the configuration stages and into building, which
finished successfully.

I have previously built llvm by hand on this machine, so I don't know
if I would encounter other problems in a vanilla environment. I may
try that out in a few days.

Gedare