crypt(3): minor formatting tweaks

clarify some of the parameters for 'setting'; avoid talking about passing
the output of crypt(3); note that for md5 and blowfish the salt is silently
truncated if it's longer than the respectively accepted length

crypt(3): Minor markup tweaks

crypt(3): Call it password hashing, not `encrypting'.

Tidy up some of the markup while here, and be consistent about
calling the neatly formatted US-ASCII string an `encoded password
hash').

crypt.3: add a reference for Argon2

Capitalize word.

crypt.3: note parallelism caveats

fix typos in man pages.

Mark up argon2 description. Restore removed lines/text from previous
commit.

adding argon2 support to libcrypt. argon2 user authentication now
available via MKARGON2=yes (3 variants supported; argon2id recommended)
before using, please read argon2 paper at
https://github.com/P-H-C/phc-winner-argon2

branches: 1.27.32;
Use major.minor for NetBSD versions.

Fix punctuation markup.

Remove trailing whitespace.

a typo and missing markup

Improve returns description from Solar Designer.

Remove trailing whitespace. Avoid xr to itself.

reflect current reality about return values.

branches: 1.20.42;
Mention pwhash(1) in a few places,
suggested in PR 31125 by Stefan Schumacher.

salt is in the second argument

branches: 1.18.2;
Remove a superfluous .sp in the SEE ALSO section.

Move UCB-licensed code from 4-clause to 3-clause licence.

Patches provided by Joel Baker in PR 22280, verified by myself.

Use
.In header.h
instead of
.Fd #include \*[Lt]header.h\*[Gt]
Much easier to read and write, and supported by groff for ages.
Okayed by ross.

New sentence, new line. From Robert Elz.

support bcrypt password. can be chosen by "blowfish" keyword in passwd.conf.
from openbsd

branches: 1.13.2;
Change Nd argument to 'password encryption', since it does not only provide
DES support. Noted by Jeremy C. Reed.

Punctuation nits.

Generate <>& symbolically.

Whitespace nits, drop unnecessary .Pps.

Take a stab at documenting non-DES password encryption.

branches: 1.8.2;
Enable decryption in crypt(), from cryptosrc-intl, and lift the updated
manual page (which describes decryption) from cryptosrc-us.

branches: 1.7.6;
More trailing white space.

Prototype has moved: add inclusion of <stdlib.h> to the synopsis of setkey().

add LIBRARY section to man page

hint that crypt() et. al. are declared in unistd.h; from Jon Buller in
PR lib/3488.

Manpage fixes from Jochen Pohl. Aligns the prototypes in the SYNOPSIS
section with the actual function declarations. See PR #1589 for details.

use the (broken) crypt.c from the 4.4BSD-Lite Foreign distribution, that
can encrypt passwords but _cannot_ decrypt anything. "real" (i.e. two-way,
unbroken) crypt() now lives in /usr/src/domestic.

always create libcrypt, and link with it where necessary. this will
make life with shared libraries happier. also, get dummy crypt out
of libc.