Reenable ghc-head

[ndmitchell]

I had to disable it since nothing worked. Hopefully will fix itself soon and can reenable.

[tomjaguarpaw]

Is there a specific problem with HEAD? I've just got a compile error where cabal can't find System.Time and Graphics.Google.Chart: https://travis-ci.org/tomjaguarpaw/haskell-opaleye/jobs/247263285#L498

From neil.cabal it seems like these should be excluded if small is defined, which you can see it is: https://travis-ci.org/tomjaguarpaw/haskell-opaleye/jobs/247263285#L473

Is this something you've seen before? Any workarounds?

[ndmitchell]

That's what I saw - seems someone broke cabal flags in some weird way. Note that HEAD /= the unreleased GHC 8.2, so HEAD is currently at it's most broken. Usually these things get fixed sooner or later.

[tomjaguarpaw]

Aha! I see I can enable testing on GHC 8.2 with GHCVER=8.2.1. That sounds like the best plan.

[ndmitchell]

Yep, HEAD is moved on - it's GHC 8.4 now :).