MFC r361294:
Update libarchive to 3.4.3

Relevant vendor changes:
PR #1352: support negative zstd compression levels
PR #1359: improve zstd version checking
PR #1348: support RHT.security.selinux from GNU tar
PR #1357: support for archives compressed with pzstd
PR #1367: fix issues in acl tests
PR #1372: child handling cleanup
PR #1378: fix memory leak from passphrase callback

MFH r324148:
Sync libarchive with vendor.

Relevant vendor changes:
PR #905: Support for Zstandard read and write filters
PR #922: Avoid overflow when reading corrupt cpio archive
Issue #935: heap-based buffer overflow in xml_data (CVE-2017-14166)
OSS-Fuzz 2936: Place a limit on the mtree line length
OSS-Fuzz 2394: Ensure that the ZIP AES extension header is large enough
OSS-Fuzz 573: Read off-by-one error in RAR archives (CVE-2017-14502)

Security: CVE-2017-14166, CVE-2017-14502