* exit after providing an estimate if -S was given. the PR used -e,
but checking around indicated prior art in Solaris usin -S.
* remove superfluous 'DUMP:' prefix in two messages
* initialise blocksperfile explicitly (not necessary, but everything
else in that section gets initialised, so be consistant :)
* display the ``pretty'' name of the dumped directory, so the user
knows if it's a subset or not
filesystem. This uses fts(3) to access the directory structure (and
not the raw device), so the standard access permissions are adhered
to (unlike dumping an entire filesystem, which just requires read
access to the raw disk device).
* Support SIGINFO status reporting.
* Remove now unused variables that previously stored the (e)uid.
* Be more informative in a couple of error messages.
