Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Clean up hardcoded ar(1) flags in the tree to use the global ARFLAGS in
share/mk/sys.mk instead.

This is part of a medium term project to permit deterministic builds of
FreeBSD.

Submitted by: Erik Cederstrand <erik@cederstrand.dk>
Reviewed by: imp, toolchain@
Approved by: cperciva
MFC after: 2 weeks

This commit was generated by cvs2svn to compensate for changes in r171831,
which included commits to RCS files with non-trunk default branches.

This commit was generated by cvs2svn to compensate for changes in r169695,
which included commits to RCS files with non-trunk default branches.