anchor.diff:  { lib
   , stdenv
   , fetchurl
  -, fetchpatch
   , meson
   , ninja
   , pkg-config
  
positive.code: 
  stdenv.mkDerivation rec {
    pname = "gtksourceview";
    version = "4.8.1";
  
    outputs = [ "out" "dev" ];
  
    src = fetchurl {
      url = "mirror://gnome/sources/${pname}/${lib.versions.majorMinor version}/${pname}-${version}.tar.xz";
      sha256 = "0WPXG1/K+8Wx7sbdhB7b283dOnURzV/c/9hri7/mmsE=";
    };
  
    patches = [
  
negative.code:     # but not from its own datadr (it assumes it will be in XDG_DATA_DIRS).
      # Since this is not generally true with Nix, let’s add $out/share unconditionally.
      ./4.x-nix_share_path.patch
    ];
  
    nativeBuildInputs = [
  