MFC r301974: ar: enable reproducible output by default when invoked as 'ar -s'

ar output is already deterministic by default for ar -q and ar -r, and
when invoked as ranlib. Make ar -s equivalent to ranlib and enable
deterministic output by default in that case too.

PR: 210330
Sponsored by: The FreeBSD Foundation

MFC r286010: ar: enable deterministic mode by default

Ar cannot handle UIDs with more than 6 digits, and storing the mtime,
uid, gid and mode provides little to negative value anyhow for ar's
uses. Turn on deterministic (-D) mode by default; it can be disabled by
the user with -U.

Also MFC follow-on fixes in r286024 and r287324.

PR: 196929
Relnotes: Yes
Sponsored by: The FreeBSD Foundation

MFC r285844: ar: add -U (unique) option to disable -D (deterministic) mode

This is required in order for us to support deterministic mode by
default. If multiple -D or -U options are specified on the command
line, the final one takes precedence. GNU ar also uses -U for this.

PR: 196929
Sponsored by: The FreeBSD Foundation

MFC r286010: ar: enable deterministic mode by default

Ar cannot handle UIDs with more than 6 digits, and storing the mtime,
uid, gid and mode provides little to negative value anyhow for ar's
uses. Turn on deterministic (-D) mode by default; it can be disabled by
the user with -U.

Also MFC follow-on fixes in r286024 and r287324.

PR: 196929
Relnotes: Yes
Sponsored by: The FreeBSD Foundation

MFC r285844: ar: add -U (unique) option to disable -D (deterministic) mode

This is required in order for us to support deterministic mode by
default. If multiple -D or -U options are specified on the command
line, the final one takes precedence. GNU ar also uses -U for this.

PR: 196929
Sponsored by: The FreeBSD Foundation