Accept a :-separated list of module names in GTK_IM_MODULE and the corresponding setting, to deal a bit better with broken situations. https://bugzilla.gnome.org/show_bug.cgi?id=603559 Patch by Akira Tagoh, backported from GTK+ 3. The backport is required because GTK+ 2 and 3 are listening to the same env vars and settings for immodules.