anchor.diff:  
   let
     versionMajor = "0.6";
  -  versionMinor = "11";
  +  versionMinor = "12";
     version = "${versionMajor}.${versionMinor}";
   in
   stdenv.mkDerivation rec {
  
positive.code: 
    src = fetchurl {
      url = "mirror://gnome/sources/libcroco/${versionMajor}/${name}.tar.xz";
      sha256 = "0mm0wldbi40am5qn0nv7psisbg01k42rwzjxl3gv11l5jj554aqk";
    };
  
    buildInputs = [
  
negative.code:     "--disable-gtk-doc"
      "--disable-gtk-doc-html"
      "--disable-gtk-doc-pdf"
      "--disable-checks"
      "--enable-Bsymbolic"
    ];
  
    passthru = {
      srcVerification = fetchurl {
        failEarly = true;
        sha256Url = "https://download.gnome.org/sources/libcroco/${versionMajor}/"
          + "${name}.sha256sum";
        inherit (src) urls outputHash outputHashAlgo;
      };
    };
  
    meta = with lib; {
      description = "Generic Cascading Style Sheet (CSS) parsing and manipulation";
      homepage = https://git.gnome.org/browse/libcroco/;
      license = licenses.lgpl2;
  