- 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

Add unistd.h to the getosreldate(3) manpage.
Update referenced example to include unistd.h per manpage.
Update example to be more style(9)-ish, silence warnings and add
FreeBSD id to the source file.

<osreldate.h> does not have a forward declration of getosreldate(), so
remove it from this man page.

MFC after: 3 days

Switch BUILD_ARCH in Makefile to use uname -p suggested by ru.
Switch strncpy to strlcpy suggested by gad and issue found by pjd.
Add to uname(3) man page describing:
UNAME_s
UNAME_r
UNAME_v
UNAME_m
Add to getosreldate(3) man page describing:
OSVERSION

Submitted by: ru, pjd/gad
Reviewed by: ru (man pages)

Fixed copyright.
Tidy up the markup.
Only describe the new, post-2.0 behavior.
Added the RETURN VALUES and ERRORS sections.

Add a manual page for getosreldate.c.

PR: 46365
Submitted by: gioria (original version)
OK'ed by: alfred (older version)