Set-up Buildbot for GDC

[Iain Buclaw via D.gnu]

Hi,

After some lamenting I've finally gotten round to setting up a 
buildbot for gdc.

https://buildbot.dgnu.org

Fitted with a smorgasbord of cross compiler builds, all of them 
are broken in one way or another, given the definition of "not 
broken" being:

  - Can build a usable compiler: all should be green here.
  - Can build druntime and libphobos: I think only ARM holds this 
title.
  - Passes the testsuite with zero failures: There exist tests 
that ICE on certain targets.

It it my hope this encourages fixing broken targets, and flags up 
regressions in build immediately, not months down the line later.

Build configuration is available on github.  Using docker so that 
anyone can set up and debug failing builds locally.

https://github.com/D-Programming-GDC/buildbot-gdc


Regards,
Iain.