For one reason or another these symbols aren't present so don't try to
make them available for linkage.

In the case of libroken these seem to be compatability bits we don't
need a thus don't compile.  For others it seems to rot upstream, but
I've not investigated deeply.

Reviewed by:	cy
Differential Revision:	https://reviews.freebsd.org/D44246

Weak crypto is provided by the openssl legacy provider which is
not load by default. Load the legacy providers as needed.

When the legacy provider is loaded into the default context the default
provider will no longer be automatically loaded. Without the default
provider the various kerberos applicaions and functions will abort().

This is the second attempt at this patch. Instead of linking
secure/lib/libcrypto at build time we now link it at runtime, avoiding
buildworld failures under Linux and MacOS. This is because
TARGET_ENDIANNESS is undefined at pre-build time.

PR:		272835
MFC after:	3 days
X-MFC:		only to stable/14
Tested by:	netchild
		Joerg Pulz <Joerg.Pulz@frm2.tum.de> (previous version)

This revision breaks Linux and MacOS cross builds because
TARGET_ENDIANNESS is not define during bootstrapping on these
platforms.

I think the correct approach would be to separate the new
fbsd_ossl_provider_load() and unload functions into their own
library (instead of libroken). This avoids the less desirable
option of including bsd.cpu.mk in secure/lib/Makefile.common,
which does build but could complicate future work.

Reported by:	jrtc27

This reverts commit cb350ba7bf7ca7c4cb97ed2c20ab45af60382cfb.

Weak crypto is provided by the openssl legacy provider which is
not load by default. Load the legacy providers as needed.

When the legacy provider is loaded into the default context the default
provider will no longer be automatically loaded. Without the default
provider the various kerberos applicaions and functions will abort().

PR:			272835
MFC after:		3 days
Differential Revision:	https://reviews.freebsd.org/D43009
Tested by:		netchild, Joerg Pulz <Joerg.Pulz@frm2.tum.de>

Upstream commit r24759 (efed563) prefixed some symbols with rk_, but
introduced 6 duplicate symbols in the version script (because the
rk_-prefixed versions of the symbols were already present).

  several new kerberos related libraries and applications to FreeBSD:
  o kgetcred(1) allows one to manually get a ticket for a particular service.
  o kf(1) securily forwards ticket to another host through an authenticated
    and encrypted stream.
  o kcc(1) is an umbrella program around klist(1), kswitch(1), kgetcred(1)
    and other user kerberos operations. klist and kswitch are just symlinks
    to kcc(1) now.
  o kswitch(1) allows you to easily switch between kerberos credentials if
    you're running KCM.
  o hxtool(1) is a certificate management tool to use with PKINIT.
  o string2key(1) maps a password into key.
  o kdigest(8) is a userland tool to access the KDC's digest interface.
  o kimpersonate(8) creates a "fake" ticket for a service.

  We also now install manpages for some lirbaries that were not installed
  before, libheimntlm and libhx509.

- The new HEIMDAL version no longer supports Kerberos 4.  All users are
  recommended to switch to Kerberos 5.

- Weak ciphers are now disabled by default.  To enable DES support (used
  by telnet(8)), use "allow_weak_crypto" option in krb5.conf.

- libtelnet, pam_ksu and pam_krb5 are now compiled with error on warnings
  disabled due to the function they use (krb5_get_err_text(3)) being
  deprecated.  I plan to work on this next.

- Heimdal's KDC now require sqlite to operate.  We use the bundled version
  and install it as libheimsqlite.  If some other FreeBSD components will
  require it in the future we can rename it to libbsdsqlite and use for these
  components as well.

- This is not a latest Heimdal version, the new one was released while I was
  working on the update.  I will update it to 1.5.2 soon, as it fixes some
  important bugs and security issues.