anchor.diff:  
   # build-tools
   , bootPkgs, alex, happy
  -, autoconf, automake, coreutils, fetchgit, fetchpatch, perl, python3
  +, autoconf, automake, coreutils, fetchurl, perl, python3
   
   , libffi, libiconv ? null, ncurses
   
  
positive.code: in
  stdenv.mkDerivation rec {
    inherit version;
    inherit (src) rev;
    name = "${targetPrefix}ghc-${version}";
  
    src = fetchgit {
      url = "git://git.haskell.org/ghc.git";
      rev = "6d7eecff7948ad77854f834f55b4d4f942276ad3";
      sha256 = "0aqy5x0b6qxhyvxw1q9pssf1xvhbyviglqkjrx4gvhbr3nax3wxp";
    };
  
    enableParallelBuilding = true;
  
negative.code:     export STRIP="${targetCC.bintools.bintools}/bin/${targetCC.bintools.targetPrefix}strip"
  
      echo -n "${buildMK}" > mk/build.mk
      sed -i -e 's|-isysroot /Developer/SDKs/MacOSX10.5.sdk||' configure
    '' + stdenv.lib.optionalString (!stdenv.isDarwin) ''
      export NIX_LDFLAGS+=" -rpath $out/lib/ghc-${version}"
  