readlink changes installed

[Jim Meyering]

I've installed the following patch from Dmitry V: Levin.

  ftp://ftp.altlinux.org/pub/people/ldv/coreutils/

In private mail (due to difficulty getting past the list software),
he wrote:

      I've implemented the changes mentioned above.  That is, "readlink -f" is
      now more compatible with prior implementations, old behaviour moved to
      "readlink -e", and your proposed relaxed -ff mode implemented as "-m".
      I don't insist on these option names though.

There's quite a bit of discussion here:
  http://bugs.debian.org/225836

This change adds two new `canonicalize' options to readlink.
I don't particularly like the new option names, so
if anyone can think of better names, possibly of the
form --canonicalize=MODE, I'd be happy to change them:

  -f, --canonicalize            canonicalize by following every symlink in
                                every component of the given path recursively;
                                all but the last path component must exist
  -e, --canonicalize-existing   canonicalize by following every symlink in
                                every component of the given path recursively,
                                all path components must exist
  -m, --canonicalize-missing    canonicalize by following every symlink in
                                every component of the given path recursively,
                                without requirements on components existence