anchor.diff:  {stdenv, fetchurl
   , libtool, autoconf, automake
   , gmp, mpfr, libffi, makeWrapper
  -, noUnicode ? false, 
  +, noUnicode ? false
  +, gcc
   }:
   let
     s = # Generated upstream information
  
positive.code:   postInstall = ''
      sed -e 's/@[-a-zA-Z_]*@//g' -i $out/bin/ecl-config
      wrapProgram "$out/bin/ecl" \
        --prefix NIX_LDFLAGS ' ' "-L${gmp.lib or gmp.out or gmp}/lib" \
        --prefix NIX_LDFLAGS ' ' "-L${libffi.lib or libffi.out or libffi}/lib"
    '';
  
negative.code:     libtool autoconf automake makeWrapper
    ];
    propagatedBuildInputs = [
      libffi gmp mpfr gcc
    ];
  in
  stdenv.mkDerivation {
  