anchor.diff:  
     isCross = ghc.isCross or false;
     isGhcjs = ghc.isGhcjs or false;
  +  packageDbFlag = if isGhcjs || versionOlder "7.6" ghc.version
  +                  then "package-db"
  +                  else "package-conf";
  +
     nativeGhc = if isCross then ghc.bootPkgs.ghc else ghc;
  +  nativeIsCross = nativeGhc.isCross or false;
  +  nativePackageDbFlag = if versionOlder "7.6" nativeGhc.version
  +                        then "package-db"
  +                        else "package-conf";
   
     newCabalFileUrl = "http://hackage.haskell.org/package/${pname}-${version}/revision/${revision}.cabal";
     newCabalFile = fetchurl {
  
positive.code:                      import Distribution.Simple
                       main = defaultMain
                     '';
  
    ghc76xOrLater = isGhcjs || stdenv.lib.versionOlder "7.6" ghc.version;
    packageDbFlag = if ghc76xOrLater then "package-db" else "package-conf";
  
    hasActiveLibrary = isLibrary && (enableStaticLibraries || enableSharedLibraries || enableLibraryProfiling);
  
  
negative.code: 
    ghcEnv = ghc.withPackages (p: haskellBuildInputs);
  
    setupBuilder = if isCross then "${nativeGhc}/bin/ghc" else ghcCommand;
    setupCommand = "./Setup";
    ghcCommand = if isGhcjs then "ghcjs" else "ghc";
    ghcCommandCaps = toUpper ghcCommand;
  