Implement pubkey support for pkg(7) bootstrap. [EN-15:18]

Approved by: so

Fix local privilege escalation in IRET handler. [SA-15:21]

Fix OpenSSH multiple vulnerabilities. [SA-15:22]

Fix insufficient check of unsupported pkg(7) signature methods.
[EN-15:15]

Approved by: so

Remove svn:mergeinfo carried over from stable/9.

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

Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

MFC r263181:

Fix ASSUME_ALWAYS_YES not being parsed properly from config after UCL conversion.

Revert r263625 to fix commit msg for blame

MFC r263180:

Fix ABI from /usr/local/etc/pkg.conf not being respected.

MFC r263180:

Fix ABI from /usr/local/etc/pkg.conf not being respected.

MFC: r241737,r246790,r247060,r247841,r248033,r248133,r255468,r256450,r256770
r256971,r256978,r257051,r257142,r257145,r257146,r257147,r257148,r257149
r257158,r257193,r257377,r257378,r257400,r257505,r257668,r257701,r257945
r258020,r258226,r258348,r258550,r259266,r259773,r259774,r259775,r262400
r262401,r262419

Sync pkg(7) with head:
- signature checking
- respecting and reading repository configurations
- support pkg bootstrap -f

Direct modifications:
- Support old libarchive
- Support old openssl API
- Define non yet existing elf macros

MFC r251560

Fix a bad calloc(3) call

MFC: r245412
Directly uses calloc(3) instread of malloc(3) + memset(3)

Reported by: Jeremy Chadwick <jdc@koitsu.org>

MFC r244553,244594,244608,244639

In preparation for making 'pkg -N' the one true method of determining
whether a system has been configured to use pkgng, cause /usr/sbin/pkg
recognise a -n option and exit with a failure code when the pkg port
is not installed

Submitted by: matthew

MFC: r243883

if PACKAGESITE url scheme is not 'file://', always try to revolv SRV records and
use them if any. It allows the bootstrap to use directly pkg.FreeBSD.org instead
of pkgbeta.FreeBSD.org

MFC: r239663, r239664

change ALWAYS_ASSUME_YES to ASSUME_ALWAYS_YES for consistency with pkg(8)
if not on a tty prompt about the missing pkg(8) but default on 'no' except if
ASSUME_ALWAYS_YES is set

MFC: r238461

Make pkg bootstrap program ask for confirmation before proceeding.

The previous behaviour was to silently download and install the pkg
package, without ever telling user about what it was doing and why.

Approved by: re, des (mentor)

Add missing \n when generating pkg.conf

Reported by: beat
Approved by: des (mentor)

MFC r234313 r234315 r234322 r234351 r234870

bootstrap tool for pkgng.
it respects PACKAGESITE, PACKAGEROOT, and a new environment variable ABI (if a
user want to use a different API from the base one for its packages)
it has no man page on purpose to avoid hidding the pkg(8) man page from the
pkgng package.
for now uses pkgbeta.FreeBSD.org as default mirror to find its package
it respects MK_PKGTOOLS

Approved by: des (mentor)

add usr.sbin/pkg which is a bootstrap tool for pkgng.
it respects PACKAGESITE, PACKAGEROOT, and a new environment variable ABI (if a user want to use a different API from the base one for its packages)
it has no man page on purpose to avoid hidding the pkg(8) man page from the pkgng package.
for now uses pkgbeta.FreeBSD.org as default mirror to find its package
it respects MK_PKGTOOLS

Approved by: des (mentor)