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

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

* fix ctm(8) to use mkstemp() instead of tempnam() for tempfile
creation.

* Tag the internal err() function with __printflike to allow checking
for non-constant format string arguments (none exist)

* Use fmtcheck() to sanitize the tar command obtained via -t to make
sure it doesn't contain extraneous format operators.

Reviewed by: mikeh
MFC after: 1 week

$Id$ -> $FreeBSD$

Use err(3). Use An/Aq for author name.

Revert $FreeBSD$ to $Id$

Make the long-awaited change from $Id$ to $FreeBSD$

This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.

Some new options, useful for restoring single files or subtrees from the
deltas.

Submitted by: A JOSEPH KOSHY <koshy@fakir.india.hp.com>