- 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

Fixed missing or broken library dependencies.

o style.Makefile(5): WARNS= -> WARNS?=.

Add spxabort, a simple netipx/spx regression test that triggers
pru_abort() by closing a listen socket while completed connections are
presenting in its listen queue. Unfortunately, it's difficult to
trigger the other two pru_abort() cases using user APIs, so they are
not covered by this test.