[bug#44700] services: setuid: More configurable setuid support.

[Christine Lemmer-Webber]

This sounds really good, thank you!

Ludovic Courtès writes:

> Howdy Christine & all!
>
> I’ve just pushed minor tweaks to ‘setuid-programs’ deprecation handling:
>
>   8b9a5641bc system: install, hurd: Use 'setuid-programs'.
>   2826f488e4 system: Accept gexps in 'setuid-programs'.
>   e0bd47b4fd system: Handle 'setuid-programs' deprecation handling as a field 
> sanitizer.
>   5291fd7a42 records: Support field sanitizers.
>
> This uses the “field sanitizers” that landed in core-updates a few weeks
> ago, and it allows us to emit only one warning per ‘setuid-programs’
> field, with source location info:
>
>   gnu/system/hurd.scm:105:2: warning: representing setuid programs with 
> file-like objects is deprecated; use 'setuid-program' instead
>
> Let me know if anything’s amiss!
>
> Ludo’.