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