Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

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

Clean up tools in tools/tools/netrate.

- tcpconnect incorrectly uses err() in usage() with errx() semantics [1]
That produces dirty error message:
tcpconnect: usage: tcpconnect [ip]: Unknown error: 0
- 64-bit aware fixes in printf() usage [2]
o netrate/juggle: time_t has arch-dependent size
o netrate/tcpconnect: don't assume %ll has always 64bit.

PR: 146088 [1], 146086 [2] (modified)
Approved by: kib (mentor)
MFC after: 1 week

Fixed error checking of pthread(3) functions.

PR: 143807
Submitted by: pluknet (partly)

Use $FreeBSD$ for the juggle version, rather than $P4$. This is good for
two reasons:

(1) juggle is now maintained in CVS, not P4, so the CVS revision number is
the authoritative one.
(2) Apparently $P4$ requires special handling and juggle was not marked
as needing it, resulting in problems for the P4 importer.

Requested by: gordon

Add 'juggle', a simple IPC micro-benchmark that uses various IPC types to
perform varying number of small IPC operations. It runs using a single
process and one thread, a single process and two threads, and using
multiple processes. Critical to its performance measure are the cost and
frequency of context switches, locking overhead, and threading
performance. The benchmark generates .csv output appropriate for reading
into a spreadsheet to generate summary statistics and perform statistical
tests easily.