Re: Miles' patch still fixes xfaces.c

[Richard Stallman <rms@gnu.org>]

    The recent change to xfaces.c has not fixed the problem that
    no one can permanently change
	    :weight bold 
    to
	    :weight normal
    in the variable `mode-line-buffer-identification', which is
    buffer-local and in other places.

I don't remember the issue.  What does it mean to "permanently change"
this?  And why can't you do it?  What happens if you try?

    Fortunately, Miles Bader posted a semi-fix on 18 Dec 2002.  This was a
    `semi-fix' because his code sometimes led to a race condition and a
    crash in Emacs.  But not very often.

    Mile's patch is

	diff -u -r1.266 xfaces.c
	--- src/xfaces.c	17 Nov 2002 23:51:19 -0000	1.266
	+++ src/xfaces.c	18 Dec 2002 05:26:34 -0000

What is the change?  (I gather the change was not installed.)

Can Miles explain what caused the problem?
Maybe we can find a better fix based on that info.