openssl: Stop dragging libpthread into every libcrypto user.

With the new _NETBSD_PTHREAD_CREATE_WEAK, libcrypto can have a call
to pthread_create without linking against libpthread, so it is not
necessary to link all libcrypto users against libpthread too.

Applications that link against libcrypto but not libpthread can't use
threaded OpenSSL functionality, of course -- OSSL_set_max_threads
will always fail in such applications.

This reverts all the makefile churn that I found for unnecessary
libpthread linkage since the openssl 3.5 import.

PR lib/59685: libcrypto should not depend on libpthread

branches: 1.16.2;
crypto needs threads

branches: 1.15.2;
Handle OpenSSL-3.x

branches: 1.14.6;
include bsd.own.mk to be sure NETBSDSRCDIR is set.

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.

Add -lcrypt where -lcrypto is specified.

Separate primes manpage from that of factor. Correct DIAGNOSTICS
information.

use NETBSDSRCDIR as appropriate

make factor work with and without openssl.

Use libcrypto's bignum support to implement a Pollard Rho factoring
algorithm so we can factorise numbers larger than a host long.

use CPPFLAGS instead of CFLAGS

branches: 1.6.2;
Back out the .PATH.c changes. The .depend problem (and others)
will be fixed using the new .NOPATH make feature instead.

Use .PATH.c: ...

merge with Lite, new RCS id conventions, etc.

specify man pages the new way.

Add RCS identifiers.

branches: 1.1.1;
Initial revision