Re: Mysterious fontification/C++ context issue - Patch for beginning-of-defun-raw.

[martin rudalics]

The slowdown comes from `open-paren-in-column-0-is-defun-start' being
nil when scanning lists backward.  You can try this with an Emacs before
Alan's change.  Open xdisp.c, put point after the braces in

void
syms_of_xdisp ()
{
...
}

and do a `backward-sexp'.  On my system it takes two seconds.  The
problem goes away when you set `open-paren-in-column-0-is-defun-start'
to t in C mode.