Add targets for release binaries? (1.3+)

[kinke via digitalmars-d-ldc]

On Friday, 5 May 2017 at 16:56:57 UTC, Adrian Matoga wrote:
> It seems that LDC doesn't use the specified triple verbatim, 
> but may modify it, e.g. "arm-linux-gnueabi" becomes 
> "arm--linux-gnueabi".

That 2nd component of the 4-component 'triple' bothers me too. 
I've only seen the values `pc`, `unknown`, `none` and now, thanks 
to you ;), even '' for it so far.