From the GTK+ website:
GTK+ and GLib 1.1.11 are now available at ftp://ftp.gtk.org/pub/gtk/v1.1/.
This is mostly a bug fix release. We have addressed (I think) the
problems we where seeing on some slackware libc5 systems. If you
still get errors on those systems, try using –disable-nls, which
now should work. Otherwise, install GNU gettext 0.10.35. GLib 1.1.x Changes
GTK+ 1.1.x Changes