For various reasons we cannot use v8.0 (prereleases) yet, but GHC v7.11.20150407

There was a compilation hiccup with polymorphic types. I corrected it in

https://github.com/ggreif/git-annex/tree/patch-1

The commit is

https://github.com/ggreif/git-annex/commit/a0ddad8d395b5eb61d1e7e6fdcbfa766c05de3d4

Cheers,

Gabor

Applied, thanks. done --Joey