bug#16526: 24.3.50; scroll-conservatively & c-mode regression

[martin rudalics]

> I don't think this happens.  back_comment (in syntax.c) assumes it
> starts outside a comment.

Does it?

>> In any case, please provide an option say
>> `c-open-paren-in-column-0-is-defun-start' which people can set to
>> avoid those scans.  The doc-string should mention that things like
>> Michael's commented out code are handled correctly iff this option is
>> nil and that long delays while working with c-mode can be sometimes
>> avoided by setting this option to t.  The default value could be
>> obviously nil.
>
> I'm hoping that the (rough) patch in one of my other emails from this
> evening will have solved the bug, so that playing around with
> open-paren-in-column-0-etc. won't be needed.
>
> As a matter of interest, with my patch applied, running your recipe on
> xdisp.c took me 4.4 seconds (including the (sit-for 3)).

Less than 8 seconds here which is quite remarkable.  Unfortunately, I
seem to have another problem now which makes `beginning-of-buffer' in
xdisp.c extremely slow with my setup (~ 30 secs).  Have to bisect my
.emacs again ...

Thanks so far, martin