Remove MKCRYPTO option.

Originally, MKCRYPTO was introduced because the United States
classified cryptography as a munition and restricted its export. The
export controls were substantially relaxed fifteen years ago, and are
essentially irrelevant for software with published source code.

In the intervening time, nobody bothered to remove the option after
its motivation -- the US export restriction -- was eliminated. I'm
not aware of any other operating system that has a similar option; I
expect it is mainly out of apathy for churn that we still have it.
Today, cryptography is an essential part of modern computing -- you
can't use the internet responsibly without cryptography.

The position of the TNF board of directors is that TNF makes no
representation that MKCRYPTO=no satisfies any country's cryptography
regulations.

My personal position is that the availability of cryptography is a
basic human right; that any local laws restricting it to a privileged
few are fundamentally immoral; and that it is wrong for developers to
spend effort crippling cryptography to work around such laws.

As proposed on tech-crypto, tech-security, and tech-userlevel to no
objections:

https://mail-index.netbsd.org/tech-crypto/2017/05/06/msg000719.html
https://mail-index.netbsd.org/tech-security/2017/05/06/msg000928.html
https://mail-index.netbsd.org/tech-userlevel/2017/05/06/msg010547.html

P.S. Reviewing all the uses of MKCRYPTO in src revealed a lot of
*bad* crypto that was conditional on it, e.g. DES in telnet... That
should probably be removed too, but on the grounds that it is bad,
not on the grounds that it is (nominally) crypto.

Don't try to clean/build or install a library here, there are only
subdirectories.

Also, bsd.lib.mk requires a defined LIB, otherwise it will generate
unwanted commands during clean. It even failed on netbsd-4 where
'rm -f' needs at least one parameter which is missing due to recent
corrections in make/vars.c.

don't set LIBDPLIBS in libpam/modules/Makefile - it is not necessary
and it interferes with the compat lib build. don't use LIB_ROOT_DIR.

Remove old kerberos library (Jukka Salmi)

pam_afslog is used in conjunction with pam_krb5 to obtain AFS tokens and
create a PAG if necessary.

Especially important for home directories on AFS.

branches: 1.8.2;
Add an S/Key PAM module.

Add pam_radius.

Build & install pam_ssh.so.0 now that libssh is available for use.

re-add inclusion of <bsd.lib.mk> for LIBDPLIBS optimization, with an
empty libinstall rule so Things Work.

Remove the inclusion of <bsd.lib.mk>. There are no libraries in this
directory, only its subdirectories.

Use LIBDPLIBS to provide the list of libraries for the modules to depend
upon, because:
* it's MUCH quicker; no need to calculate the OBJDIRS of every library
we might require in every subdir.
(make obj drops from 21s to 3s on my system.)
* it's more robust when building to a fresh DESTDIR.

- NetBSD build glue
- Warning fixes
- RCSID's

branches: 1.1.1;
Initial revision