update-gtk-immodules is a wrapper around gtk-query-immodules-2.0 that tries to help with multilib installations. It is meant to be used in %post scripts of rpm packages that install input method modules for GTK+ 2.x.
It needs to be given a GNU-style host triplet as argument, such as "x86_64-redhat-linux-gnu". This argument determines where the tool saves the gtk.immodules file that it creates. It must be the same as the host triplet that GTK+ was configured with.
$libdir/gtk-2.0/2.10.0/immodules.cache - the file created by update-gtk-immodules.