bug#32932: 27.0.50; render bugs on macOS Mojave

[Eli Zaretskii]

> Date: Thu, 8 Nov 2018 15:21:17 +0000
> From: Alan Third <alan@idiocy.org>
> Cc: Eli Zaretskii <eliz@gnu.org>, 32932@debbugs.gnu.org,
>       boris@d12frosted.io
> 
> We could try and force Emacs to bend to the NS way by forcing
> expose_frame and friends to draw WHENEVER REQUESTED, but I don’t know
> how practical that is, and it would mean making changes in xdisp.c
> which may be unwelcome.

What exactly do you mean by WHENEVER REQUESTED?  As opposed to what
alternative?