Revision 235633

MFC r234353:

  Upgrade our copy of llvm/clang to trunk r154661, in preparation of the
  upcoming 3.1 release (expected in a few weeks).  Preliminary release
  notes can be found at: <http://llvm.org/docs/ReleaseNotes.html>

MFC r234982:

  Upgrade our copy of llvm/clang to r155985, from upstream's release_31
  branch.  This brings us very close to the 3.1 release, which is planned
  for May 14th.

MFC r235058:

  Make sure a few new internal clang headers get installed, I missed these
  in the last import.  They are sometimes needed when you want to use
  advanced instructions.

  Also, add clang's internal stdalign.h header to ObsoleteFiles.inc, since
  it is redundant: we already have a stdalign.h header in /usr/include.

  Pointy hat to:	dim
  PR:		kern/167574
  Submitted by:	jkim
  Reported by:	Oliver Hartmann <ohartman@zedat.fu-berlin.de>