Revert r330897:

This was intended to be a non-functional change. It wasn't. The commit
message was thus wrong. In addition it broke arm, and merged crypto
related code.

Revert with prejudice.

This revert skips files touched in r316370 since that commit was since
MFCed. This revert also skips files that require $FreeBSD$ property
changes.

Thank you to those who helped me get out of this mess including but not
limited to gonzo, kevans, rgrimes.

Requested by: gjb (re)

Partial merge of the SPDX changes

These changes are incomplete but are making it difficult
to determine what other changes can/should be merged.

No objections from: pfg

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Add a missing break in the TCP case.

Reviewed by: bms
MFC after: 1 week

The use of snprintf() to append to a buffer is not valid according to C99

Commit IPv6 support for FAST_IPSEC to the tree.
This commit includes all remaining changes for the time being including
user space updates.

Submitted by: bz
Approved by: re

Initial import of RFC 2385 (TCP-MD5) digest support.

This is the second of two commits; bring in the userland support to finish.

Teach libipsec and setkey about the tcp-md5 class of security associations,
thus allowing administrators to add per-host keys to the SADB for use by
the tcpsignature_compute() function.

Document that a single SPI must be used until such time as the code which
adds support to the SPD to specify flows for tcp-md5 treatment is suitable
for production.

Sponsored by: sentex.net

- errx() doesn't need `\n'.
- use %u for unsigned variable.

Obtained from: KAME

stop use of NI_WITHSCOPEID. it was deprecated.

Obtained from: KAME

Remove multi-line __P() usage.

Remove __P() usage.

Add __FBSDID()s to libipsec

synchronize with latest kame tree.

behavior change: policy syntax was changed. you may need to update your
setkey(8) configuration files.

libipsec and IPsec related apps. (and some KAME related man pages)

Reviewed by: freebsd-arch, cvs-committers
Obtained from: KAME project