Update bsdtar --owner and --group support

[kwrobot]

Original issue 167 created by kientzle on 2011-08-14T17:52:36.000Z:

GNU tar recently extended --owner and --group to support arbitrary names and ID values, for creating archives on systems with dissimilar user bases.  It's a nice idea and one that bsdtar should probably support.

Begin forwarded message:

From: Paul Eggert <eggert@cs.ucla.edu>
Date: August 13, 2011 10:29:23 AM PDT
To: Thayne Harbaugh <thayne.l.h@gmail.com>
Cc: 136231@bugs.debian.org, bug-tar@gnu.org
Subject: Re: [Bug-tar] Failure with --owner and --group when names cannot be    mapped to IDs

tar: --owner and --group names and numbers
The --owner and --group options now accept operands of the form
NAME:NUM, so that you can specify both symbolic name and numeric
ID for owner and group.  Also, in these options, NAME no longer
needs to be present in the current host's user and group
databases; this implements Debian enhancement request 136231
<http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=136231> reported
by Mark W. Eichin, communicated by Thayne Harbaugh to bug-tar in
<http://lists.gnu.org/archive/html/bug-tar/2011-08/msg00001.html>.

[kwrobot]

Comment #1 originally posted by kientzle on 2011-11-24T19:59:18.000Z:

bsdtar already has --gid, --gname, --uid, --uname options that provide the same functionality.  If someone wants to implement GNU tar-compatible --owner and --group options, I'm happy to review patches, but this isn't a priority for me.