pax: remove 4.4BSD compatibility
Sponsored by: Klara, Inc.
(cherry picked from commit 30c30e220af30fbe8896a2bc4769b9ffd7fb43fb)
pax: comment typo fixes from NetBSD / OpenBSD.
Sponsored by: Klara, Inc.
(cherry picked from commit 0266a5d610be4fb546475934125a037ca5748184)
pax: name all supported formats.
Sponsored by: Klara, Inc.
(cherry picked from commit a8e8a914456878a67dfc5ef6f917a04be2e6a0c7)
pax: update date parsing code (from OpenBSD)
Sponsored by: Klara, Inc.
MFC after: 1 week
(cherry picked from commit d05e43bc0d5705919d057793aaa3e6d3df65f815)