I tried building XEmacs with GTK support from CVS. First, the configure script wrote this: checking for GTK configuration script... configure: warning: Found unsupported version of GTK: configure: warning: Found unsupported version of GTK: gtk-config checking gtk version... 1.2.9 Is 1.2.9 really unsupported? If so, why, and which is the supported one? Then, my XEmacs crashed on startup. Lisp stacktrace claims the crash happened in input-pending-p, and a C backtrace was unavailable. Then I recompiled with -g and without optimizations and was fortunately able to repeat the crash. As far as I can tell, enqueue_event is called with dispatch_event_queue_tail being a Lisp Objetc with all-zero bit pattern (illegal). This looked like a dumping bug (I use pdump), so I decided to staticpro dispatch_event_queue_tail. And lo and behold, the problem went away. If anything else goes wrong, I'll be sure to let you know. :-)