MFC r224638,224640,224642 (by brooks):

MFC r224638,224640,224642 (by brooks):

  Add support for dynamically adjusted buffers to allow the full use of
  the bandwidth of long fat pipes (i.e. 100Mbps+ trans-oceanic or
  trans-continental links).  Bandwidth-delay products up to 64MB are
  supported.

  Also add support (not compiled by default) for the None cypher.  The
  None cypher can only be enabled on non-interactive sessions (those
  without a pty where -T was not used) and must be enabled in both
  the client and server configuration files and on the client command
  line.  Additionally, the None cypher will only be activated after
  authentication is complete.  To enable the None cypher you must add
  -DNONE_CIPHER_ENABLED to CFLAGS via the make command line or in
  /etc/make.conf.

  This code is a style(9) compliant version of these features extracted
  from the patches published at:

  http://www.psc.edu/networking/projects/hpn-ssh/

  Enable keyword expansion for $FreeBSD$ on files.

MFC r225852 (by des):

  Regenerate (ssh_namespace.h) after application of the HPN patch.

Discussed with:	brooks

git-svn-id: svn://svn.freebsd.org/base/stable/8@228152 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f