Sync libarchive with vendor.
Vendor bugfixes:
libarchive #831:
Spelling fixes
libarchive #832:
Relax sanity checks of number fields in tar header even more
OSS-Fuzz #16:
Fix possible hang in uudecode_filter_read()
OSS-Fuzz #220:
Reject an 'ar' filename table larger than 1GB or a filename larger
than 1MB.
MFC after: 1 week