- Copy stable/10@296371 to releng/10.3 in preparation for 10.3-RC1
builds.
- Update newvers.sh to reflect RC1.
- Update __FreeBSD_version to reflect 10.3.
- Update default pkg(8) configuration to use the quarterly branch.

Approved by: re (implicit)

MFC r264400,r265836:

r264400:

NO_MAN= has been deprecated in favor of MAN= for some time, go ahead
and finish the job. ncurses is now the only Makefile in the tree that
uses it since it wasn't a simple mechanical change, and will be
addressed in a future commit.

r265836:

Remove last two NO_MAN= in the tree. In both of these cases, MAN= is
what is needed.

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

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

Start the dreaded NOFOO -> NO_FOO conversion.

OK'ed by: core

For variables that are only checked with defined(), don't provide
any fake value.

Add a simple exercise suite for IP-level socket options. The suite
atempts to read and write various IP-level socket options as root and
nobody, making sure the initial values are as expected, that they can
be changed to valid values and take effect, etc. No attempt is made
to check for the correct implementation of side effects (such as
changes in packet headers) as yet.

The IP options section is currently broken but will be fixed shortly.

Not all multicast options are currently tested.