tar -x without clobbering directories

[Michael ODonnell]

My Debian system's tar identifies itself as "tar (GNU tar) 1.22" and
the output generated with --help includes the following excerpt where
that --no-overwrite-dir option sounds like what you wanted:

 Overwrite control:

  -k, --keep-old-files       don't replace existing files when extracting
      --keep-newer-files     don't replace existing files that are newer than
                             their archive copies
      --no-overwrite-dir     preserve metadata of existing directories
      --overwrite            overwrite existing files when extracting
      --overwrite-dir        overwrite metadata of existing directories when
                             extracting (default)
      --recursive-unlink     empty hierarchies prior to extracting directory
      --remove-files         remove files after adding them to the archive
  -U, --unlink-first         remove each file prior to extracting over it
  -W, --verify               attempt to verify the archive after writing it