anchor.diff:    checkTarget = "test";
   
     postInstall = ''
  -    paxmark m $out/lib/${preReleaseName}/bin/{ghc,haddock}
  +    paxmark m $out/lib/${name}/bin/{ghc,haddock}
   
       # Install the bash completion file.
       install -D -m 444 utils/completion/ghc.bash $out/share/bash-completion/completions/ghc
  
positive.code:   name = "ghc-${version}";
  
    src = fetchurl {
      url = "https://downloads.haskell.org/~ghc/${version}/${preReleaseName}-src.tar.xz";
      sha256 = "1w4k0n23b9fg8kmarqhfamzpmf91p6jcdr6xlwzfmb4df2bd9hng";
    };
  
  
negative.code: let
    inherit (bootPkgs) ghc;
    version = "8.2.1";
  
    commonBuildInputs = [ alex autoconf automake ghc happy hscolour perl python3 sphinx ];
    commonPreConfigure =  ''
      sed -i -e 's|-isysroot /Developer/SDKs/MacOSX10.5.sdk||' configure
    '' + stdenv.lib.optionalString (!stdenv.isDarwin) ''
      export NIX_LDFLAGS="$NIX_LDFLAGS -rpath $out/lib/ghc-${version}"
    '' + stdenv.lib.optionalString stdenv.isDarwin ''
      export NIX_LDFLAGS+=" -no_dtrace_dof"
    '' + stdenv.lib.optionalString enableIntegerSimple ''
  