- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

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

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

Add a regression test for listen()'s backlog argument, both at time of
creation and at time of update using an additional call to listen().
This test also exercises SO_LISTENQLIMIT, a forthcoming socket option
that allows the retrieval (but not setting) of the queue limit.

Discussed with: andre