anchor.diff:  
   let
     pname = "TeXmacs";
  -  version = "1.99.2";
  +  version = "1.99.10";
     common = callPackage ./common.nix {
       inherit tex extraFonts chineseFonts japaneseFonts koreanFonts;
     };
  
positive.code: { stdenv, callPackage,
    fetchurl, guile_1_8, qt4, xmodmap, which, makeWrapper, freetype,
    tex ? null,
    aspell ? null,
    ghostscriptX ? null,
    extraFonts ? false,
    chineseFonts ? false,
  
negative.code:   name = "${pname}-${version}";
  
    src = fetchurl {
      url = "https://www.texmacs.org/Download/ftp/tmftp/source/TeXmacs-${version}-src.tar.gz";
      sha256 = "1k12bkcik7mv93q0j7q3b77x8s6rmvlb23s3v7nnzdwjxlp5lph2";
    };
  
    cmakeFlags = [
      # Texmacs' cmake build as of writing defaults to Qt5,
      # but we haven't updated to that yet.
      "-DTEXMACS_GUI=Qt4"
    ];
  
    enableParallelBuilding = true;
  
    nativeBuildInputs = [ cmake pkgconfig ];
    buildInputs = [
      guile_1_8
      qt4
      makeWrapper
      ghostscriptX
      freetype
      libjpeg
      sqlite
      git
      python3
    ];
    NIX_LDFLAGS = [ "-lz" ];
  
    postInstall = "wrapProgram $out/bin/texmacs --suffix PATH : " +
          (if ghostscriptX == null then "" else "${ghostscriptX}/bin:") +
          (if aspell == null then "" else "${aspell}/bin:") +
          (if tex == null then "" else "${tex}/bin:") +
          (if git == null then "" else "${git}/bin:") +
          (if python3 == null then "" else "${python3}/bin:") +
          "${xmodmap}/bin:${which}/bin";
  
    inherit (common) postPatch;
  