anchor.diff:  let withLwt = lwt != null; in
   
   buildOcaml rec {
  -  version = "0.1.1";
  +  version = "0.1.1a";
     name = "notty";
   
     minimumSupportedOcamlVersion = "4.02";
  
positive.code: { stdenv, buildOcaml, fetchFromGitHub, findlib
  , result, uucp, uuseg, uutf
  , lwt     ? null }:
  
  
negative.code:   src = fetchFromGitHub {
      owner  = "pqwy";
      repo   = "notty";
      rev    = "53f5946653490fce980dc5d8cadf8b122cff4f19";
      sha256 = "0qmwb1hrp04py2i5spy0yd6c5jqxyss3wzvlkgxyl9r07kvsx6xf";
    };
  
    patches = [ (fetchpatch {
      url = https://github.com/dbuenzli/notty/commit/b0e12930acc26d030a74d6d63d622ae220b12c92.patch;
      sha256 = "0pklplbnjbsjriqj73pc8fsadg404px534w7zknz2617zb44m6x6";
    })];
  
    buildInputs = [ findlib opam topkg ocb-stubblr ];
    propagatedBuildInputs = [ result uucp uuseg uutf ] ++
                            optional withLwt lwt;
  
    buildPhase = topkg.buildPhase
    + " --with-lwt ${if withLwt then "true" else "false"}";
  
    inherit (topkg) installPhase;
  
    meta = {
      inherit (src.meta) homepage;
  