Re: bug in building 21.1

[Richard Stallman]

    I read thru the INSTALL and saw I should be using libungif-4.1.0b1,
    which I hadn't prior to my first build. I obtained this release and
    installed it prior to building emacs-21.1. As per my previous messages,
    I've been dying in temacs and emacs on exit in the destructors for
    libungif. This much you know.

    I just reconfig'd emacs with --without-gif, and rebuilt. No more
    problem. That may not be very interesting to you, but it does
    demonstrate that the problem is some emacs-ungif thing; it does kind of
    eliminate the problem as an emacs thing trying to make ungif look bad.
    If you have any suggestions of things for me to try, let me know.

That is an important step forward in localizing the problem,
but in order to figure out how to fix the bug, we need to know
precisely what causes the crash.  Can anyone else reproduce this?
Can anyone debug it?