anchor.diff:    stdenv, lib,
     src, patches, version, qtCompatVersion,
   
  -  coreutils, bison, flex, gdb, gperf, lndir, perl, pkgconfig, python2,
  +  coreutils, bison, flex, gdb, gperf, lndir, perl, pkgconfig, python3,
     which,
     # darwin support
     darwin, libiconv,
  
positive.code:     ++ lib.optional (postgresql != null) postgresql;
  
    nativeBuildInputs =
      [ bison flex gperf lndir perl pkgconfig python2 which ];
  
    propagatedNativeBuildInputs = [ lndir ];
  
  
negative.code:     );
  
    buildInputs =
      [ python3 ]
      ++ lib.optionals (!stdenv.isDarwin)
      (
        [ libinput ]
        ++ lib.optional withGtk3 gtk3
  