bug#51734: 29.0.50; got slow

[Eli Zaretskii]

> Date: Thu, 11 Nov 2021 21:02:18 +0900
> From: Katsumi Yamaoka <yamaoka@jpl.org>
> Cc: 51734@debbugs.gnu.org
> 
> On Thu, 11 Nov 2021 10:09:30 +0200, Eli Zaretskii wrote:
> >> Probably what I should do could be bisecting the recent commits.
> > That'd be best, if you can.  Thanks.
> 
> I did it and found the revision that causes this problem on at
> least Cygwin-64.  That is d5bb053.  However, as there are a lot
> of changed files in a single commit, it seems hard to me to find
> what change is the real cause.  I need a skillful Cygwin player.

That's strange: that changeset changed just the docs, and the only
changes in code are in xwidget.c (which your build shouldn't compile)
and in keyboard.c, where the changes just remove redundant braces, and
again mostly in places that are built only when xwidgets are
supported.

If you revert only the changes in keyboard.c, does the problem go
away?