bug#66245: [PATCH] ; Silence macOS 14 warning

[Alan Third <alan@idiocy.org>]

On Wed, Sep 27, 2023 at 09:00:45PM +0200, Eshel Yaron via Bug reports for GNU Emacs, the Swiss army knife of text editors wrote:
> Tags: patch
> 
> Hi,
> 
> After updating to macOS 14 (and rebuilding Emacs), I see the following
> warning whenever I start Emacs:
> 
>     WARNING: Secure coding is not enabled for restorable state! Enable secure coding by implementing NSApplicationDelegate.applicationSupportsSecureRestorableState: and returning YES.
> 
> This patch does exactly what the warning suggests, and it silences the
> warning.
> 
> TBH I'm not entirely sure I understand the implications of implementing
> `applicationSupportsSecureRestorableState`.  IIUC it makes Emacs opt-in
> to the "secure state restoration" mechanism in contrast to a former
> (supposedly less secure) mechanism, but AFAICT Emacs doesn't opt-in to
> state restoration in the NS port in the first place...

A description of what this fixes is here:

    https://sector7.computest.nl/post/2022-08-process-injection-breaking-all-macos-security-layers-with-a-single-vulnerability/

I'm not sure if making this change will affect us, as I don't think we
support saved states, although I could be wrong.

Is it possible for you to try a before and after test of how Emacs
handles saving the state over a reboot? That is, have a running Emacs
with open files and reboot, tick the "reopen windows when logging back
in" option, and see if it behaves differently with this patch applied
and not applied?

If it doesn't then I think this is probably safe and won't affect us,
so we should apply it. Otherwise we'll need to examine what's changed
and see if we can work around it.

Thanks!
-- 
Alan Third