anchor.diff:  WORKDIR /home/ghc
   USER ghc
   
  -ENV PATH /opt/ghc/8.2.2/bin:/opt/cabal/2.0/bin:/php/arcanist/bin:$PATH 
  +ENV PATH /opt/ghc/8.2.2/bin:/opt/cabal/2.2/bin:/php/arcanist/bin:$PATH
   
   # Build dependencies for nofib-analyse
  -RUN cabal update && cabal install html regex-compat 
  +RUN cabal update && cabal install html regex-compat
   
  
positive.code:   xsltproc docbook-xsl \
    python-sphinx \
    texinfo \
    
    # Needed for testing current HEAD
    python3 \
    
    # Needed for running nofib
    time \
  
  
negative.code:   # mentioned on the GHC wiki
    autoconf automake libtool make libgmp-dev ncurses-dev g++ python bzip2 ca-certificates \
    llvm \
    llvm-3.9 llvm-4.0 \
    xz-utils \
  
    ## install minimal set of haskell packages
    # from darinmorrison/haskell
    ghc-8.2.2 \
    alex \
    cabal-install-2.2 \
    happy \
  
    # development conveniences
  