MFC r271597:

Pull in r217410 from upstream llvm trunk (by Bob Wilson):

  Set trunc store action to Expand for all X86 targets.

  When compiling without SSE2, isTruncStoreLegal(F64, F32) would return
  Legal, whereas with SSE2 it would return Expand. And since the Target
  doesn't seem to actually handle a truncstore for double -> float, it
  would just output a store of a full double in the space for a float
  hence overwriting other bits on the stack.

  Patch by Luqman Aden!

This should fix clang -O0 on i386 assigning garbage to floats, in
certain scenarios.

PR:		187437
Submitted by:	cebd@gmail.com
Approved by:	re (marius)
Obtained from:	http://llvm.org/viewvc/llvm-project?rev=217410&view=rev
MFC r270673:
Announce SCTP support in the kern.features sysctl variables.

MFC r270859:
Enable SCTP support. It runs perfectly fine on a Wandboard quad.

MFC r271204 with manual intervention:
Fix the handling of sysctl variables when used with VIMAGE.
While there do some cleanup of the code.

MFC r271209:
Fix a leak of an address, if the address is scheduled for removal
and the stack is torn down.
Thanks to Peter Bostroem and Jiayang Liu from Google for reporting the
issue.

MFC r271219:
Use SYSCTL_PROC instead of SYSCTL_VNET_PROC.
Suggested by: glebius@

MFC r271221:
Use union sctp_sockstore instead of struct sockaddr_storage. This
eliminates some warnings when building in userland.
Thanks to Patrick Laimbock for reporting this issue.
Remove also some unnecessary casts.
There should be no functional change.

MFC r271228:
Address another warnings reported by Patrick Laimbock when compiling
in userspace. While there, improve consistency.

MFC r271230:
Address warnings generated by the clang analyzer.

Approved by: re (kib)
MFC r271644:
Add quirks to disable READ CAPACITY (16) for PNY USB 3.0 Flash Drives.

Submitted by:	Sean Fagan <sef@ixsystems.com>
Approved by:	re (kib)
MFC r271643:
Chunk IDs are 8 bit entities, not 16 bit.
Thanks to Peter Kasting from Google for drawing
my attention to it.

MFC r271665:
The MTU is handled as a 32-bit entity within the SCTP stack.
This was reported by Peter Kasting from Google.

MFC r271670:
Make a type conversion explicit. When compiling this code on
Windows as part of the SCTP userland stack, this fixes a
warning reported by Peter Kasting from Google.

MFC r271672:
Small cleanup which addresses a warning regaring the truncation
of a 64-bit entity to a 32-bit entity. This issue was reported by
Peter Kasting from Google.

MFC r271673:
Use a consistent type for the number of HMAC algorithms.
This fixes a bug which resulted in a warning on the userland
stack, when compiled on Windows.
Thanks to Peter Kasting from Google for reporting the issue and
provinding a potential fix.

MFC r271674:
Add a explict cast to silence a warning when building
the userland stack on Windows.
This issue was reported by Peter Kasting from Google.

Approved by: re (kib)