MFC r330245:

Allow the "@" and "!" characters in passwd file GECOS fields.

Two PRs (152084 & 210187) request allowing the "@" and/or "!"
characters in the passwd file GECOS field. The man page for pw does
not mention that those characters are disallowed, Linux supports those
characters in this field, and the "@" character in particular would be
useful for storing email addresses in that field.

PR: 152084, 210187
Submitted by: jschauma@netmeister.org, Dave Cottlehuber <dch@freebsd.org>
Reported by: jschauma@netmeister.org, Dave Cottlehuber <dch@freebsd.org>
Sponsored by: Dell EMC

MFC r322678: pw useradd: Validate the user name before creating the entry

Previouly it was possible to create users with spaces in the name with:
pw useradd -u 1234 -g 1234 -n 'test user'

The "-g 1234" is relevant, without it the name was already rejected
as expected:

[fk@test ~]$ sudo pw useradd -u 1234 -n 'test user'
pw: invalid character ` ' at position 4 in userid/group name

Bug unintentionally found with a salt config without explicit name entry:

test user:
user.present:
- uid: 1234
- gid: 1234
- fullname: Test user
- shell: /usr/local/bin/bash
- home: /home/test
- groups:
- wheel
- salt

"Luckily" salt modules rarely bother with input validation either ...

PR: 221416
Submitted by: Fabian Keil
Approved by: re (kib)
Obtained from: ElectroBSD

MFC: r315912 (by eugen@) and r315935

Properly initialise with content of pw.conf(5) that was mistakenly ignored.
Also, respect "defaultgroup" if specified there.

Add a regression test

PR: 217934
Submitted by: Victor Sudakov <vas@mpeks.tomsk.su>

MFC r315776:

Rename tests from <foo> to <foo>_test to match the FreeBSD test suite
naming scheme

usr.bin/diff/diff_test was renamed to usr.bin/diff/netbsd_diff_test
to avoid collisions with the renamed FreeBSD test.