- 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

WARNS=3'ify.

Don't assume sizeof(long) = sizeof(int) on x86; use int
instead of long types for low-level locks.

Add prototypes for some internal libc functions that are
wrapped by the library as cancellation points.

Add memory barriers to alpha atomic swap functions (submitted
by davidxu).

Requested by: bde

Add some very beta amd64 bits. These will also need some tweaking.