'RELENG_6_0_0_RELEASE'.

This commit was manufactured to restore the state of the 6.0-RELEASE image.

  - Print space character in show_stat(). Remove a lot of priuntf(" ").
  - Utilize show_stat() in sidewaysintpr() loop. This makes periodic
    statistics to honor -h flag.

Approved by:	re (kensmith)

  List -W as one of the meaningful options to the -i (interfaces)
  display of netstat(1).

Approved by:	re (hrs)

  Add a new switch -h for interface stats mode, which prints all interface
  statistics in human readable form.

  In collaboration with:	vsevolod
  Reviewed by:			cperciva

Approved by:	re (kensmith)

  Modify "netstat -mb" to use libmemstat(3) when acting on a live system,
  with a number of positive benefits:

  - Start using UMA(9) statistics for mbufs and clusters, which avoids
    using the mbuf allocator statistics which suffer from races under
    load on SMP.  This should eliminate "negative" mbuf counts in
    netstat -mb.

  - We are now able to track cached (free) mbufs and clusters and count
    it towards memory allocated by the network stack.

  - We are now also able to track memory allocated to mbuf tags since
    libmemstat(3) can also query malloc(9).  We don't print this except
    as part of the total (for now - #if 0).

  - We are now able to track mbuf/cluster/packet allocation failures,
    although they are not currently printed (#if 0).

  - Don't print out sfbuf statistics when running on a kernel core, as
    currently that code is able only to query sysctl for statistics.

mbuf.c:1.44:

  Since libmemstat(3) now supports its own error management mechanism,
  use that instead of trying to use errno, in order to produce a
  sensible error message.

Approved by:	re (kensmith)

  Print newly exported pfsync statistics with netstat(8).

  Requested by:   glebius

Approved by:	re (kensmith)

NI_WITHSCOPEID, and our getaddrinfo(3) does nothing special
for it, now.