anchor.diff:  {stdenv, fetchurl
   , libtool, autoconf, automake
  -, gmp, mpfr, libffi
  +, gmp, mpfr, libffi, makeWrapper
   , noUnicode ? false, 
   }:
   let
  
positive.code:     sha256="16ab8qs3awvdxy8xs8jy82v8r04x4wr70l9l2j45vgag18d2nj1d";
    };
    buildInputs = [
      libtool autoconf automake
    ];
    propagatedBuildInputs = [
      libffi gmp mpfr
  
negative.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"
    '';
    meta = {
      inherit (s) version;
  