ar: diff reduction against ELF Tool Chain
- Drop exit status from bsdar_errc. ELF Tool Chain always returns EXIT_FAILURE in bsdar_errc.
- Remove ar_mode_* wrappers and call ar_read_archive / ar_write_archive directly.
Obtained from: ELF Tool Chain
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D31496
(cherry picked from commit d20e9e02db3dde383c3de1ce8cec3a8c35b3eee6)
(cherry picked from commit c5bf58add0d523fc6e6546f3fc10d0c8b972e8e7)
(cherry picked from commit 086f09087713e3af0a28d296a2372071b72211ef)
(cherry picked from commit 57aaefdceccdd590f81af4b274c7a3ee61ae62f1)
(cherry picked from commit 866c807472619371adcb2a0409a9287748a52654)
(cherry picked from commit d8ffb451194ec2d91a549e0682370f312d0ecdd3)