anchor.diff:  
     ghcEnv = ghc.withPackages (p: haskellBuildInputs);
   
  -  setupBuilder = if isGhcjs then "${nativeGhc}/bin/ghc" else ghcCommand;
  +  setupBuilder = if isCross then "${nativeGhc}/bin/ghc" else ghcCommand;
     setupCommand = "./Setup";
     ghcCommand = if isGhcjs then "ghcjs" else "ghc";
     ghcCommandCaps = toUpper ghcCommand;
  
positive.code: 
    isCross = ghc.isCross or false;
    isGhcjs = ghc.isGhcjs or false;
    nativeGhc = if isCross then ghc.bootPkgs.ghc else ghc;
  
    newCabalFileUrl = "http://hackage.haskell.org/package/${pname}-${version}/revision/${revision}.cabal";
    newCabalFile = fetchurl {
  
negative.code:                      import Distribution.Simple
                       main = defaultMain
                     '';
  
    hasActiveLibrary = isLibrary && (enableStaticLibraries || enableSharedLibraries || enableLibraryProfiling);
  
  