While here, also remove two forgotten descriptions for long obsolete
devices.

ok phessler

the SHA512/256 functions as well.

ok jmc naddy

with different magic numbers, so we need to add some functions instead
of just asking the user to truncate as desired. Sigh.
SHA512 is quite a bit faster than SHA256 on 64 bit CPUs,
but 256 bit hashes are usually quite sufficient. Best of both.
ok deraadt tom

from Jacob Berkman, ok beck@

OK many

shortly when we use the hardware thread register in userland

Discussed with and loved by many.
OK tedu@, tom@, deraadt@.

part of the original ISC license that we use in OpenBSD.  Done for
files were Henning is the original author.
OK henning@ deraadt@

ok deraadt@ yasuoka@ reyk@

ok beck

tested by many (thanks!) ok tedu, guenther@

ok krw@ millert@

ok jca@ krw@

as readlink() will tell you that more cheaply.
ok millert@

ok deraadt@

ok deraadt@

ok deraadt@

ok deraadt@

functions out the way of the main body;
ok guenther

Merge the manual pages and call them deprecated there.
ok and manpage tweak jmc@, ok natano@

remove some references to differences between versions 6 and 7.
ok jmc, millert, tedu

workarounds.  Some of them will soon stand in the way of armv7.
Off to the attic you go.

ok jung@ (some time ago) phessler@

ok deraadt@

pseudo-interfaces.
This unbreak vlan(4) on top of tap(4) since the refactoring to turn it
MP-safe.
ok claudio@, deraadt@