bug#37832: internal-border face ignored in Emacs 26.3 for macOS

[Eli Zaretskii]

> From: Andrea Cardaci <cyrus.and@gmail.com>
> Date: Sun, 20 Oct 2019 15:25:54 +0200
> 
> The `internal-border` face is ignored and the `default` face
> background is used instead. I'm experiencing this with Emacs 26.3
> installed with `brew cask install emacs`.
> 
> Reproduce with the following `.emacs`:
> 
> (custom-set-variables
>  '(default-frame-alist '((internal-border-width . 100))))
> 
> (custom-set-faces
>  '(default ((t (:background "black" :foreground "white"))))
>  '(internal-border ((t (:background "red")))))
> 
> Works fine on Linux version 26.1.

Sounds like a macOS specific issue, because this works fine for me on
MS-Windows both with Emacs 26.3 and with the current master branch
(which will eventually become Emacs 27).