- Copy stable/10@285827 to releng/10.2 in preparation for 10.2-RC1
builds.
- Update newvers.sh to reflect RC1.
- Update __FreeBSD_version to reflect 10.2.
- Update default pkg(8) configuration to use the quarterly branch.[1]

Discussed with: re, portmgr [1]
Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

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

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

Remove struct ia64_itir and use a plain old uint64_t instead.

Redefine a PTE as a 64-bit integral type instead of a struct of
bit-fields. Unify the PTE defines accordingly and update all
uses.

Better preserve the original protection for the mappings we maintain.
The hardware always gives read access for privilege level 0, which
means that we cannot use the hardware access rights and privilege
level in the PTE to test whether there's a change in protection. So,
we save the original vm_prot_t in the PTE as well.
Add pmap_pte_prot() to set the proper access rights and privilege
level on the PTE given a pmap and the requested protection.

The above allows us to compare the protection in pmap_extract_and_hold()
which was missing. While in pmap_extract_and_hold(), add pmap locking.

While here, clean up most (i.e. all but one) PTE macros we inherited
from alpha. They were either unused, used inconsistently, badly named
or simply weren't beneficial. We save the wired and managed state of
the PTE in distinct (bit) fields.

While in pte.h, s/u_int64_t/uint64_t/g

pmap locking obtained from: alc@
feedback & review by: alc@

Define PS and VE fields of region register correctly.

Factor out PTE and related definitions from pmap.h - they are useful in
the loader.