Bump dependency versions for GHC 8.0

[bgamari]

No description provided.

[hsenag]

I'd prefer to wait for a release candidate of GHC 8 so I can test myself on Windows and Linux - but if base 4.9 won't get any further API changes now and you need this soon, I can apply it quicker.

[cnd]

@hsenag
I understand that as maintainer you can wait a lot but just note that there are should be a lot of users who will not wait and they all will be forced to do same things by themselves. I strongly suggest to accept this. At least haskell platform will not be released without cabal install and you can't build cabal install without accepting this changes. This is one of core libraries and if someone on this earth is caring about ecosystem...

[hsenag]

FYI at the moment I can build with GHC 8.0 RC1 but I can't run the tests, because of snoyberg/conduit#242

I'm happy to apply this if it's obstructing people. But is it just wanted on github, or on hackage too?

I wonder if the people working at the bleeding edge should just pass --allow-newer to Cabal instead of me providing "official" but untested versions. I know that doing that doesn't work at present because of Build-Tools, but I take @hvr's point that I should just remove that.

[cnd]

Currently that's not very first and not the only obstructing thing and really can wait either in github and hackage, I personally don't need it having those changes done locally so it's still being just up to you.

[hsenag]

I've dropped the build-tools line on hackage, and I've pushed a base 4.10 patch to a GHC8 branch for now: https://github.com/haskell/HTTP/tree/ghc8

[ndmitchell]

For info, this is obstructing my testing of my downstream packages that use HTTP. Not fatal, but a release with a fix would be useful.

[hvr]

@ndmitchell GHC 8 compatible http://hackage.haskell.org/package/HTTP-4000.3.3 was released recently

[ndmitchell]

Thanks @hvr! (And now I move on to raising tickets in things above HTTP, HeinrichApfelmus/vault#23)