Use lockless quota checks in qsync and qsyncvp.

No strong objections from: kib, mckusick
MFC after:	1 week
Fix the type of pte_pa as when it is passed into _kvm_pa2off it is either
a uint64_t or a pointer to an off_t. With it being a u_long can result in
incorrect values being returned.
Add an "empty" Makefile.pc98 because it doesn't need/want HYPERV. It
is not relevant to the hardware it runs on.
Fix the reported streams in a SCTP_STREAM_RESET_EVENT, if a
sent incoming stream reset request was responded with failed
or denied.
Thanks to Peter Bostroem from Google for reporting the issue.

MFC after: 3 days
MK_ARB_EABI was removed in r272350 so remove the documentation.
Per r273155, HYPERV is built by default on platforms where it makes
sense and ignored on others.
Document that WITHOUT_TOOLCHAIN causes headers to not be installed, not
just programs.
Regenerate src.conf.5 after:

r273170:
  MK_ARB_EABI was removed in r272350 so remove the documentation.
r273171:
  Per r273155, HYPERV is built by default on platforms where it makes
  sense and ignored on others.
r273172:
  Document that WITHOUT_TOOLCHAIN causes headers to not be installed, not
  just programs.