CPU_BUSY_CYCLE(): A new MI statement for busy loop power reduction

The new CPU_BUSY_CYCLE() may be put in a busy loop body so that CPU can reduce
power consumption, as Linux's cpu_relax() and FreeBSD's cpu_spinwait().  To
start minimally, use PAUSE on i386/amd64 and empty on others.  The name is
chosen following the existing cpu_idle_*() functions.  Naming and API may be
polished later.

OK kettenis@
Suspicions confirmed by sthen's searching that nothing uses ossl_ssize_t
except embedded openssl's in other trees.
Don't hold the kernel lock while halting a processor. Assert if we detect
this happening.

ok kettenis@, deraadt@
Remove unused files.
Even though occasional commits did happen to these files, they still
specify directories like /usr/share/man/cat4/tahoe, /usr/include/pascal,
/usr/X11R4 and so on, so calling them "maintained" would seem a bold claim.
ok sthen@ henning@
Make sure we leave OPENSSL_NO_PSK in the conf files so things
can know...
ok jsing@
Clean up versioning and remove #ifdefs that we do not define.

ok beck@
Provide correct version details for LibreSSL.

ok beck@ deraadt@ miod@
Simplify the code that handles the HTTP headers by using an RB tree
with associated lists instead of the complicated lookup table and
"others" list.  This might add a little malloc overhead for common
headers but also fixes some issues like the handling of repeated
headers -  for example, handling of multiple "Set-Cookie" headers.

ok bluhm@ (regress part)
ok benno@
Missing initialization; OpenSSL PR#3289 and #3345 via OpenSSL trunk.
Missing initialization for error line in error paths; from Coverity via
OpenSSL trunk.
updated inode format, whitespace, re-formatting
Make CMS_decrypt_set1_pkey() return an error if no recipient type matches,
instead of returning a random key; OpenSSL PR #3348 via OpenSSL trunk
Missing calloc() return value check in dgram_sctp_ctrl(); from Kurt Roeckx via
OpenSSL trunk
Remove rfc 4620 Node Information Query support (from the kernel).

ok henning@ stu@, Yay! weerd@
clean up after previous: zap rfc 4620 from sysctl(3) too.
ok jmc
In ssl3_get_client_key_exchange() parsing a GOST session key, invoke the
regular ASN.1 parser rather than trying to handroll one and potentially
misbehave; OpenSSL PR #3335 via OpenSSL trunk.
whatever mickey had to drink 13 years ago, he's not going to find it again. so
just remove the comment and unneeded functionality which has been "#ifdef notused"
for the past 13 years.

OK uebayasi@
with out-of-order extraction, match tempnames to item names
display the extraction tally only if verbose
When looking for the issuer of a certificate, if the current candidate is
expired or not valid yet, continue looking; only return an expired certificate
if no valid certificates have been found.

OpenSSL PR #3359 via OpenSSL trunk.