Update Elixir to 1.8.0

[Dave Cottlehuber]

On Tue, 5 Feb 2019, at 00:24, Mark Felder wrote:
> Hello,
> 
> I have a review of a port I've been using for a while. Elixir 1.8.0 
> works great on FreeBSD
> 
> https://reviews.freebsd.org/D19080
> 
> -- 
>   Mark Felder
>   ports-secteam & portmgr member
>   feld at FreeBSD.org

Generally LGTM, but I am not sure what to do about bumping OTP release.

In January I proposed we deprecate OTP < 18 completely (who uses them and they are more & more broken wrt expected TLS standards) but there was no feedback at all. If we bump OTP -> 20 (which seems completely sensible to me) I'd advocate doing both at the same time.

But then we probably need an exprun to see what else breaks.

A+
Dave