[bug#61462] Add support for file capabilities(7)

[Ludovic Courtès]

Hey Tobias & all,

Thanks for pushing this series!!

I followed up with these commits:

  ce40b1c655 install: Set ‘privileged-programs’ rather than ‘setuid-programs’.
  b51990057c system: hurd: Empty default ‘privileged-programs’ list.
  2cccf2f11c services: Truly mark ‘setuid-program-service-type’ as deprecated.
  52ac2db924 services: privileged-program: No libcap when cross-compiling to 
the Hurd.

They restore support for Guix System cross-compilation to GNU/Hurd, as
tested with:

  make check-system TESTS=childhurd

Let me know if I got anything wrong!

Note that there’s a number of internal uses of
‘setuid-program-service-type’ that we should update at some point (no
rush, though).

Thanks,
Ludo’.