bug#54329: 28.0.91; custom-prompt-customize-unsaved-options does not return nil

[Eli Zaretskii]

> From: Sebastian Miele <iota@whxvd.name>
> Cc: 54329@debbugs.gnu.org
> Date: Thu, 10 Mar 2022 18:17:02 +0100
> 
> The reason that the behavior of
> ‘custom-prompt-customize-unsaved-options’ changed from version 27.2 to
> 28 almost certainly is the following:
> 
> ‘custom-prompt-customize-unsaved-options’ calls ‘customize-unsaved’
> which ends with call to ‘custom-buffer-create’.  The definition of
> ‘custom-buffer-create’ changed from Emacs 27.2 to Emacs 28.  In Emacs
> 27.2 it probably always returned non-nil.  In Emacs 28 it always
> returns nil.
> 
> However, the (and ...) form in
> ‘custom-prompt-customize-unsaved-options’ depends on
> ‘customize-unsaved’ to always return non-nil in order to be correct.
> 
> ‘custom-prompt-customize-unsaved-options’ always had the bug reported
> here.  It just did not manifest before ‘custom-buffer-create’ was
> changed from Emacs 27.2 to Emacs 28.

Thanks, this was the information I missed.

I installed a minor variation of your changes on the emacs-28 branch.
Please take a look.