MFC r339746,339751,339794,340866,340939,342042:

MFC r339746,339751,339794,340866,340939,342042:
Sync libarchive with vendor.

Relevant vendor changes:
  PR #1013: Add missing h_base offset when performing absolute seeks in
            xar decompression
  PR #1023: Support extracting extattrs as non-root on non-user-writeable
            files
  PR #1061: Add support for extraction of RAR v5 archives
  PR #1066: Fix out of bounds read on empty string filename for gnutar, pax
            and v7tar
  PR #1067: Fix temporary file path buffer overflow in tests
  IS #1068: Correctly process and verify integer arguments passed to
            bsdcpio and bsdtar
  PR #1070: Don't default XAR entry atime/mtime to the current time
  PR #1080: Spelling fixes
  PR #1084: RAR5 reader bugfixes
  PR #1091: fix use-after-free in delayed newc link processing
  PR #1092: Fix a few obvious resource leaks and strcpy() misuses
  IS #1096: Support extracting ACLs with in-entry comments (GNU tar)
  PR #1102: RAR5 reader - fix big-endian problems
  PR #1105: Fix various crash, memory corruption and infinite loop conditions

  RAR5 reader: FreeBSD build platform fixes for powerpc(64), mips(64),
               sparc64 and riscv64
  RAR5 reader: more maybe-uninitialized size_t fixes for riscv64
               FreeBSD build