Initial commit to include virtual machine images as part
of the FreeBSD release builds.

This adds a make(1) environment variable requirement,
WITH_VMIMAGES, which triggers the virtual machine image
targets when not defined to an empty value.

Relevant user-driven variables include:

 o VMFORMATS:	The virtual machine image formats to create.
   Valid formats are provided by running 'mkimg --formats'

 o VMSIZE:	The size of the resulting virtual machine
   image.  Typical compression is roughly 140Mb, regardless
   of the target size (10GB, 15GB, 20GB, 40GB sizes have been
   tested with the same result).

 o VMBASE:	The prefix of the virtual machine disk images.
   The VMBASE make(1) environment variable is suffixed with
   each format in VMFORMATS for each individual disk image, as
   well as '.img' for the source UFS filesystem passed to
   mkimg(1).

This also includes a new script, mk-vmimage.sh, based on how
the VM images for 10.0-RELEASE, 9.3-RELEASE, and 10.1-RELEASE
were created (mk-vmimage.sh in ^/user/gjb/thermite/).

With the order in which the stages need to occur, as well as
sanity-checking error cases, it makes much more sense to
execute a shell script called from make(1), using env(1) to
set specific parameters for the target image than it does to
do this in make(1) directly.

Sponsored by:	The FreeBSD Foundation
Use VMBASE in place of a hard-coded filename in the CLEANFILES list.

Sponsored by:	The FreeBSD Foundation
Do not transfer unneeded training zero bytes in INQUIRY response.

It is an addition to r269631.
- Cleanups pc98 code.
- Remove unworked formats.
Remove extra '\'.
Reduce diffs against i386.
MFi386: r261520

  Drop the 3rd clause from all 3 clause BSD licenses.
Regenerate usb.conf

MFC after:	3 days
Instead of creating the full range of possible ports, try to figure
out the actual number of so-called "embedded jacks" which are present
when a USB MIDI device is attaching.

MFC after:	3 days
MFi386: r268974

  Supress clang warning for FreeBSD printf %b and %D formats.
MFi386: r261567

  Switch from lib/libstand to sys/boot/libstand32.
- Remove empty wrappers ether_poll_[de]register_drv(). [1]
- Move polling(9) declarations out of ifq.h back to if_var.h
  they are absolutely unrelated to queues.

Submitted by:	Mikhail <mp lenta.ru> [1]
- Cosmetic changes.
- Reduce diffs against i386.
MFi386: Enable QUOTA, PRINTF_BUFR_SIZE and puc.
Remove duplicate declaraton of the if_inc_counter() function after r272244.
if_var.h has the expected on and if_var.h include ifq.h and thus we get
duplicates.  It seems only one cavium ethernet file actually includes ifq.h
directly which might be another cleanup to be done but need to test first.
Move the unconditional #include of net/ifq.h to the very end of file.
This seems to allow us to pass a universe with either clang or gcc
after r272244 (and r272260) and probably makes it easier to untabgle
these chained #includes in the future.
Remove a 'set -x' that snuck in during testing.

Sponsored by:	The FreeBSD Foundation
Checksum coverage values larger than 65535 for UDPLite are invalid.
Check for this when the user calls setsockopt using UDPLITE_{SEND,RECV}CSCOV.

Reviewed by: kevlo
MFC after: 3 days
release/Makefile:
  Connect the virtual machine image build to the release
  target if WITH_VMIMAGES is set to a non-empty value.

release/release.sh:
  Add WITH_VMIMAGES to RELEASE_RMAKEFLAGS.

release/release.conf.sample:
  Add commented entries for tuning the release build if the
  WITH_VMIMAGES make(1) environment variable is set to
  a non-empty value.

Sponsored by:	The FreeBSD Foundation
Convert most BPF_TAP users to BPF_MTAP.

MFC after:	2 weeks