Truth of the matter is, I skimmed the output of ./configure --help and
missed the part that said using lucid dialogs really meant using motif. I
never meant to use motif, and this never bit me in the past because I never
had motif installed on my system.
Since contemporary hardware makes recompiling XEmacs take no more than five
minutes (if that), and since the test case that causes the crash is trivial
to reproduce, I'm willing to investigate this problem further, or test
fixes, or whatever.
Faried.