sandbox-darwin.c: sandbox.h is deprecated

[Marius Schamschula]

Hi there,

Thank you for all the efforts on openssh portable over the years!

sandbox-darwin.c: has had a good long run.

Unfortunately, Apple has deprecated sandbox.h in favor of a newer App Sandbox API, see

https://developer.apple.com/documentation/security/app-sandbox#//apple_ref/doc/uid/TP40011183

Building openssh 10.3p1 now fails using Xcode 27-Beta.

Note: Apple seems to have worked around this issue internally, as they are shipping openssh 10.3p1, LibreSSL 3.3.6 with the new Beta.

Marius
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Marius Schamschula