xfce.thunar: patch to avoid error

«the desktop file … is in an insecure location»
which pops up when invoking desktop files that are
symlinks to the /nix/store

this error was added by this commit:

https://github.com/xfce-mirror/thunar/commit/1ec8ff89ec5a3314fcd6a57f1475654ddecc9875

«Only allow direct execution of desktop files in an
XDG directory and if they are executable.»

pkgs/desktops/xfce/core/thunar-build.nix

@@ -17,6 +17,10 @@ stdenv.mkDerivation rec {
 
   patches = [ ./thunarx_plugins_directory.patch ];
 
+  postPatch = ''
+    sed -i -e 's|thunar_dialogs_show_insecure_program (parent, _(".*"), file, exec)|1|' thunar/thunar-file.c
+  '';
+
   buildInputs = [
     pkgconfig intltool
     gtk dbus_glib libstartup_notification libnotify libexif pcre udev
@@ -35,4 +39,4 @@ stdenv.mkDerivation rec {
     platforms = stdenv.lib.platforms.linux;
     maintainers = [ stdenv.lib.maintainers.eelco ];
   };
-}
+}