rednotebook: fix "Namespace Gtk not available" error

gobject-introspection setup hook looks at the packages at $hostOffset to
populate GI_TYPELIB_PATH. We need gtk3 to be there.

pkgs/applications/editors/rednotebook/default.nix

@@ -30,6 +30,10 @@ buildPythonApplication rec {
     "--suffix XDG_DATA_DIRS : $XDG_ICON_DIRS:$GSETTINGS_SCHEMAS_PATH"
   ];
 
+  # Until gobject-introspection in nativeBuildInputs is supported.
+  # https://github.com/NixOS/nixpkgs/issues/56943#issuecomment-472568643
+  strictDeps = false;
+
   meta = with lib; {
     homepage = http://rednotebook.sourceforge.net/;
     description = "A modern journal that includes a calendar navigation, customizable templates, export functionality and word clouds";