anchor.diff:  
   let
     onOff = value: if value then "ON" else "OFF";
  -  tex = texlive.combine {
  -    inherit (texlive)
  -      scheme-medium varwidth multirow hanging adjustbox collectbox stackengine
  -      sectsty tocloft newunicodechar etoc;
  -  };
   in
   stdenv.mkDerivation rec {
     pname = "fltk";
  
positive.code: , withDocs ? true
  , doxygen
  , graphviz
  , texlive
  
  , withExamples ? true
  , withShared ? true
  
negative.code:   ] ++ lib.optionals withDocs [
      doxygen
      graphviz
    ];
  
    buildInputs = lib.optionals stdenv.hostPlatform.isDarwin [
  