I built GHC HEAD from git yesterday (using GHC 7.10.3 on Mac OS 10.9.5), and the haddock I got dies with 

    bash-3.2$ haddock --version

    dyld: Symbol not found: _ghc_GHC_modInfoExportszugo_info

      Referenced from: /Users/conal/git-repos/ghc-2016-04-05/inplace/lib/bin/haddock

      Expected in: /Users/conal/git-repos/ghc-2016-04-05/compiler/stage2/build/libHSghc-8.1-ghc8.1.20160405.dylib

     in /Users/conal/git-repos/ghc-2016-04-05/inplace/lib/bin/haddock

    Trace/BPT trap: 5

Luckily, I have a working haddock from 2016-03-07 sources that I copied into my new GHC bin (~/git-repos/ghc-2016-04-05/inplace/bin/) for now.

-- Conal