Make cgi 7.8 ready

[jhenahan]

Builds under the latest platform and 7.8-RC2.

A different approach than the one taken in the other PR.

There may be a more elegant solution, I just followed the
common pattern I've seen in a few other libraries.

The version bump may also be overly aggressive.

[relrod]

@andersk ping! Can this be merged? Current cgi on hackage does not build on 7.8.3.

[mpickering]

I tried this patch and the build still failed on MonadCatchIO-mtl.

[cheecheeo]

@mpickering using "The Glorious Glasgow Haskell Compilation System, version 7.8.3" and running cabal -j install with a fresh cabal sandbox works fine for me. Does it fail on a different version of the compiler?

[mpickering]

Ok this succeeds in a fresh sandbox but fails with mtl-2.2.1. Sorry for the incorrect report.

Configuring MonadCatchIO-mtl-0.3.0.5...
Building MonadCatchIO-mtl-0.3.0.5...
Preprocessing library MonadCatchIO-mtl-0.3.0.5...
[1 of 1] Compiling Control.Monad.CatchIO ( Control/Monad/CatchIO.hs, dist/dist-sandbox-b6663262/build/Control/Monad/CatchIO.o )

Control/Monad/CatchIO.hs:55:15: Not in scope: ‘E.block’

Control/Monad/CatchIO.hs:56:15: Not in scope: ‘E.unblock’
Failed to install MonadCatchIO-mtl-0.3.0.5

[cheecheeo]

@mpickering Is failing to build with mtl-2.2.1 a blocker for haskell-cgi? See also: #1 I'm pretty sure the intent of this ticket is just to get haskell-cgi working with GHC 7.8

[cheecheeo]

cgi successfully builds with mtl-2.2.1 with the following cabal command:
cabal -j install --constraint=mtl==2.2.1 --constraint=MonadCatchIO-mtl==0.3.1.0 --allow-newer=MonadCatchIO-transformers I'll reach out to the MonadCatchIO-mtl maintainer to up the bounds of the package.

[jhenahan]

@andersk ping!

[cheecheeo]

For those following this thread. I'm working with @cartazio to push a new version to hackage here: cheecheeo/haskell-cgi#1 If you'd like to comment or follow along.