anchor.diff:  , fetchurl
   , tk
   , tcllib
  -, makeWrapper
  +, tcl
   , tkremind ? true
   }:
   
   let
  -  inherit (lib) optional optionalString;
  -  tclLibraries = lib.optionals tkremind [ tcllib tk ];
  -  tclLibPaths = lib.concatStringsSep " "
  -    (map (p: "${p}/lib/${p.libPrefix}") tclLibraries);
  +  inherit (lib) optional optionals optionalString;
  +  tclLibraries = optionals tkremind [ tcllib tk ];
     tkremindPatch = optionalString tkremind ''
       substituteInPlace scripts/tkremind --replace "exec wish" "exec ${tk}/bin/wish"
     '';
   in
  -stdenv.mkDerivation rec {
  +tcl.mkTclDerivation rec {
     pname = "remind";
     version = "03.03.06";
   
  
positive.code:     sha256 = "sha256-lpoMAXDJxwODY0/aoo25GRBYWFhE4uf11pR5/ITZX1s=";
    };
  
    nativeBuildInputs = optional tkremind makeWrapper;
    propagatedBuildInputs = tclLibraries;
  
    postPatch = ''
  
negative.code:     ${tkremindPatch}
    '';
  
    meta = with lib; {
      homepage = "https://dianne.skoll.ca/projects/remind/";
      description = "Sophisticated calendar and alarm program for the console";
  