Merge r990,r1044 from libarchive.googlecode.com:
read_support_format_raw() allows people to exploit libarchive's
automatic decompression support by simply stubbing out the
archive format handler.
The raw handler is not enabled by support_format_all(), of course.
It bids 1 on any non-empty input and always returns a single
entry named "data" with no properties set.