bug#43381: 27.1.50; Maybe wrong cursor FG color in NS port

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: alan@idiocy.org,  43381@debbugs.gnu.org,  dale@codefu.org
> Date: Fri, 18 Sep 2020 13:06:16 +0200
> 
> > The solution to that doesn't have to be what you propose, it can be
> > something else, which doesn't ignore our usual face-merging.  We just
> > need to use a mechanism we have for this purpose: the
> > distant-foreground color of a face.
> 
> The vast majority of faces don't have a distant-foreground, I think?
> And that's in relation to the region face, not the cursor?

I thought to define it only for the cursor face.  And if that needs
some special treatment on the C level, it shouldn't be hard to tweak
that.