SHA256 would make libarchive based application to give:
archive_read_extract(): Lzma library error: Corrupted input data
(Internally this is LZMA_DATA_ERR)
However, the libmd version of SHA256 is supposed to give same result
as the bundled version do, and xz(1) is not affected.
As a precaution, revert the SHA256 portion of r281316 for now until
we figure out why it breaks libarchive interoperability as we can't
yet rule out this change have introduced an ABI breakage.
62376cf1de