anchor.diff:  
     outputs = [ "out" "dev" ];
   
  -  nativeBuildInputs = [ meson ninja pkg-config gettext gobject-introspection glib ]
  -    ++ lib.optional stdenv.hostPlatform.isDarwin fixDarwinDylibNames;
  +  nativeBuildInputs = [ meson ninja pkg-config gettext glib ]
  +    ++ lib.optional stdenv.hostPlatform.isDarwin fixDarwinDylibNames
  +    ++ lib.optional withIntrospection gobject-introspection;
   
     propagatedBuildInputs = [
       # Required by atk.pc
  
positive.code: { lib, stdenv, fetchurl, meson, ninja, gettext, pkg-config, glib
  , fixDarwinDylibNames, gobject-introspection, gnome
  }:
  
  let
  
negative.code:     # meson builds an incorrect .pc file
      # glib should be Requires not Requires.private
      ./fix_pc.patch
    ];
  
    mesonFlags = [
      "-Dintrospection=${lib.boolToString withIntrospection}"
    ];
  
    doCheck = true;
  