MFC r254224, r254294, r254328, r258307, r258309, r258310, r258314,

MFC r254224, r254294, r254328, r258307, r258309, r258310, r258314,
    r258317, r258319, r258320, r258669, r258786, r258853, r258949,
    r259079, r259246:

r254224:
  Update the wrapper script to 'release.sh', as used by the
  FreeBSD Release Engineering Team as of 9.2-RELEASE.

  Document that a cross-build release is possible by setting
  the TARGET and TARGET_ARCH variables.

  Include an example of using release.sh with and without the
  optional configuration file.

  Document the supported release.sh configuration file variables.

  Update the 'cdrom' target output file to disc1.iso.

  Update the 'memstick' target output file to memstick.img.

  Add attributions for the last major updates to this manual page.

  Fix some mdoc(7) style nits.

r254294:
  Remove the defaults for TARGET/TARGET_ARCH.

  Note that WORLD_FLAGS and KERNEL_FLAGS set the number of
  make(1) jobs only on SMP-capable systems.

r254328:
  Remove the {SRC,DOC,PORT}REVISION variables from release(7), and
  update the default {SRC,DOC,PORT}BRANCH defaults.

r258307:
  Add a script and configuration files to fetch pre-built packages
  from pkg.FreeBSD.org for inclusion on release medium (dvd1.iso).

  The script sources ${.CURDIR}/${TARGET}/pkg-stage.conf, which sets
  several environment variables, such as the pkg(8) ABI, PACKAGESITE,
  PKG_DBDIR, and PKG_CACHEDIR.  PKG_CACHEDIR is set to the directory
  on the release medium used by bsdconfig(8) (/packages/${ABI}).  ABI
  is determined by output of 'make -C /usr/src/release -V REVISION'.
  See pkg.conf(5) for descripton on other variables set here.

  The list of packages to include are set within the configuration
  file.

  The script and configuration files are intended to be run by the
  'make dvd' target within the release directory, and assume the
  release is built within a chroot environment (such as by using
  release.sh).

r258309:
  Set the PKG_CACHEDIR directory to 'dvd/' instead of 'release/'
  in preparation of adding a 'dvd1.iso' target.

r258310:
  Add the 'dvd1.iso' target.  This mimics the 'release.iso' target,
  with the additional step of fetching packages for inclusion on the
  dvd image.

  The 'pkg-stage' target is used to run 'scripts/pkg-stage.sh' if
  the '${TARGET}/pkg-stage.conf' configuration file exists (currently
  only amd64 and i386).

  Allow dvd1.iso to be skipped if NODVD=1.

r258314:
  Fix how ABI is evaluated so it matches more than a dot-zero
  case.

r258317:
  Document the 'dvdrom' target.

r258319:
  Remove WITHOUT_PROFILE=1 for the dvd1.iso medium.

r258320:
  Simplify PKG_ABI for pkg-stage.sh.

r258669:
  Document the dvdrom target and NODVD variable.

r258786:
  Move OPTIONS_UNSET outside of the PBUILD_FLAGS variable, otherwise
  the textproc/docproj port build fails.

r258853:
  Turn off the dvdrom target by default.  dvd1.iso is now built by
  specifying 'WITH_DVD=1' during 'make release'.

r258949:
  Ensure WITH_DVD is not empty to prevent 'WITH_DVD= ' from evaluating
  to true.

r259079:
  Add WITH_DVD to RELEASE_RMAKEFLAGS, otherwise it is not actually
  passed to 'make release'.

r259246:
  Prevent release build errors found during snapshot builds where if
  NOPORTS=1, pkg-stage.sh cannot build the ports-mgmt/pkg port if
  WITH_DVD=1.

Tested against:	stable/9@r259512
Sponsored by:	The FreeBSD Foundation

git-svn-id: svn://svn.freebsd.org/base/stable/9@259530 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f