anchor.diff:    # These packages try to execute non-existent external programs.
     cmaes = dontCheck super.cmaes;                        # http://hydra.cryp.to/build/498725/log/raw
     dbmigrations = dontCheck super.dbmigrations;
  -  euler = dontCheck super.euler;                        # https://github.com/decomputed/euler/issues/1
     filestore = dontCheck super.filestore;
     getopt-generics = dontCheck super.getopt-generics;
     graceful = dontCheck super.graceful;
  
positive.code:   # https://github.com/bos/snappy/issues/1
    snappy = dontCheck super.snappy;
  
    # https://github.com/kim/snappy-framing/issues/3
    snappy-framing = dontHaddock super.snappy-framing;
  
    # https://ghc.haskell.org/trac/ghc/ticket/9625
    vty = dontCheck super.vty;
  
  
negative.code:   ABList = dontCheck super.ABList;
  
    # sse2 flag due to https://github.com/haskell/vector/issues/47.
    vector = if pkgs.stdenv.isi686 then appendConfigureFlag super.vector "--ghc-options=-msse2" else super.vector;
  
    conduit-extra = if pkgs.stdenv.isDarwin
      then super.conduit-extra.overrideAttrs (drv: { __darwinAllowLocalNetworking = true; })
  