libarchive: merge vendor bugfixes
Bugfixes:
IS #1672 and OSS-Fuzz #38766: (zip reader) fix possible out-of-bounds read in zipx_lzma_alone_init() PR #1676: (mtree reader) remove the unused variable "detected_bytes" PR #1674: (doc) fix use of At mdoc(7) macro in cpio.5
MFC after: 3 days