- 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

Major update for unix_cmsg from Andrey Simonenko.

Quoting the submitter:
- Added tests for SCM_BINTIME, LOCAL_PEERCRED, cmsghdr.cmsg_len
- Code that checks correctness of groups was corrected (getgroups(2) change)
- unix_cmsg.c was completely redesigned and simplified
- Use less timeout value in unix_cmsg.c for faster work
- Added support for not sending data in a message, not sending data and
data array associated with a cmsghdr structure in a message
- Existent tests were improved
- unix_cmsg.t was redesigned and simplified

Correctness of unix_cmsg verified on 7.1-STABLE, 9.1-STABLE and 10-CURRENT.

PR: bin/131567
Submitted by: Andrey Simonenko <simon@comsys.ntu-kpi.kiev.ua>
MFC after: 2 weeks

o Add a collection of regression tests for ancillary (control)
data passing for unix domain sockets, stream and datagram.

There are 15 tests:

Test/Type of socket STREAM DGRAM
----------------------------------------------------------------------
Sending, receiving cmsgcred 1 6
Receiving sockcred (listening socket has LOCAL_CREDS) 2 n/a
Receiving sockcred (accepted socket has LOCAL_CREDS) 3 n/a
Receiving sockcred n/a 7
Sending cmsgcred, receiving sockcred 4 8
Sending, receiving timestamp 5 9
Sending, receiving cmsgcred (no control data) 10 13
Sending cmsgcred, receiving sockcred (no control data) 11 14
Sending, receiving timestamp (no control data) 12 15

Currently we pass 8 tests. All the rest marked as TODO.

PR: kern/90800
Submitted by: Andrey Simonenko