As discussed in http://code.google.com/p/libarchive/issues/detail?id=348
the read_concatenated_archives option provides functionality similar to
the GNUtar --ignore-zeros option in order to support reading from
archives which have been concatenated together.
Changes in v2:
* Replace recursion with looping for reading concatenated archives.
Changes in v3:
* Improve comments about archive format detection and looping when
reading concatenated archives.
Signed-off-by: Kevin Locke <kevin@kevinlocke.name>