busybox

Patch from Matthew S. Wood:
> The following patch adds support for the -S and -b flags to `ln'.  These
> flags [especially -b] are used extensively in Debian pre and post
> installation scripts.

Comments from Vladimir Oleynik influenced the final patch, and I also ripped
out the in-file changelog since it belongs here.  At the time, it said:

/* Apr 15, 2004      Matthew S. Wood    (mwood@realmsys.com)
 *
 * Implement '-b' (backup) flag.
 * Implement '-S' (backup suffix) flag.
 *
 *
 * Mar 16, 2003      Manuel Novoa III   (mjn3@codepoet.org)
 *
 * Fixed bug involving -n option.  Essentially, -n was always in effect.
 */