bug#16736: Compiling a Lisp file causes display to flash off and on

[Eli Zaretskii]

> Date: Sun, 16 Feb 2014 11:31:29 +0100
> From: martin rudalics <rudalics@gmx.at>
> CC: Eli Zaretskii <eliz@gnu.org>, 16736@debbugs.gnu.org
> 
>  > Bisected to:
>  >
>  >     revno: 115971
>  >     committer: martin rudalics <rudalics@gmx.at>
>  >     branch nick: trunk
>  >     timestamp: Sat 2014-01-11 10:31:09 +0100
>  >     message:
>  >       Fix handling of internal borders (Bug#16348).
> 
> Does anything change when you set the frame's internal border width to
> zero?  Does anything change when you disable the calls to
> x_clear_under_internal_border?  If so, can you spot one of these calls
> as the offending one?  I'm yet too silly to understand what's going on
> here.

Btw, the bug was about non-toolkit builds, but at least one of the
hunks affects toolkit builds as well.  Not sure if that was intended.