Created attachment 5720 update intltool Switches from AC_PROG_INTLTOOL to IT_PROG_INTLTOOL. See https://bugzilla.xfce.org/show_bug.cgi?id=8930 for details.
Thanks, pushed to master: http://git.xfce.org/xfce/thunar/commit/?id=703157492975fa79ddb0b94d518301fdf2187838
Marking as fixed.