MFC r259197:
Do not DELAY() for P-state transition unless we want to see the result.

Intel manual says: "If a transition is already in progress, transition to
a new value will subsequently take effect. Reads of IA32_PERF_CTL determine
the last targeted operating point."  So seems it should be fine to just
trigger wanted transition and go.  Linux does the same.
MFC r258683:
Escape special XML chars, returned by some devices, confusing XML parsers.
MFC r260102:

Similar to r260020, only use -fms-extensions with gcc, for all other
modules which require this flag to compile.  Use a GCC_MS_EXTENSIONS
variable, defined in kern.pre.mk, which can be used to easily supply the
flag (or not), depending on the compiler type.

MFC r260322:

In addition to r260102, also define GCC_MS_EXTENSIONS in bsd.sys.mk,
since kernel module builds do not use kern.pre.mk.
MFC r260334:

Split the last gcc-specific flags off into CFLAGS.gcc.  This also
removes the need to use -Qunused-arguments for clang throughout the
tree.

MFC r260369:

Apply band-aid for 32-bit compat libs failures after r260334: put back
-Qunused-arguments for clang for now, until I can figure out a way to
make it unneeded in all scenarios.  Sorry about the breakage.
MFC r260358

Fix a cut and paste error.
MFC r259634:
  Prevent users from deactivating the last component of a mirror.

MFC r259929:
  Add an ability to stop gmirror and clear its metadata in one command.
  This fixes the problem, when gmirror starts again just after stop.

  The problem occurs when gmirror's component has geom label with equal size.
  E.g. gpt and gptid have the same size as partition, diskid has the same
  size as entire disk. When gmirror's geom has been destroyed, glabel
  creates its providers and this initiate retaste.

  Now "gmirror destroy" command is available. It destroys geom and also
  erases gmirror's metadata.

PR:		184985
MFC r260151 (by adrian):
  Use an RLOCK here instead of an RWLOCK - matching all the other calls
  to lla_lookup().

  This drastically reduces the very high lock contention when doing parallel
  TCP throughput tests (> 1024 sockets) with IPv6.

MFC r260187:
  lla_lookup() does modification only when LLE_CREATE is specified.
  Thus we can use IF_AFDATA_RLOCK() instead of IF_AFDATA_LOCK() when doing
  lla_lookup() without LLE_CREATE flag.

MFC r260217:
  Add IF_AFDATA_WLOCK_ASSERT() in case lla_lookup() is called with
  LLE_CREATE flag.
[automated] Merge in upstream-github/stable/9