Pull in r196874 from upstream llvm trunk:

  Fix a crash that occurs when PWD is invalid.

  MCJIT needs to be able to run in hostile environments, even when PWD
  is invalid. There's no need to crash MCJIT in this case.

  The obvious fix is to simply leave MCContext's CompilationDir empty
  when PWD can't be determined. This way, MCJIT clients,
  and other clients that link with LLVM don't need a valid working directory.

  If we do want to guarantee valid CompilationDir, that should be done
  only for clients of getCompilationDir(). This is as simple as checking
  for an empty string.

  The only current use of getCompilationDir is EmitGenDwarfInfo, which
  won't conceivably run with an invalid working dir. However, in the
  purely hypothetically and untestable case that this happens, the
  AT_comp_dir will be omitted from the compilation_unit DIE.

This should help fix assertions occurring with ports-mgmt/tinderbox,
when it is using jails, and sometimes invalidates clang's current
working directory.

Reported by:	decke
MFC after:	2 weeks
X-MFC-With:	r261991
Merge from head up to r262611.
Merge the projects/clang-sparc64 branch back to head.  This brings in
several updates from the llvm and clang trunks to make the sparc64
backend fully functional.

Apart from one patch to sys/sparc64/include/pcpu.h which is still under
discussion, this makes it possible to let clang fully build world and
kernel for sparc64.

Any assistance with testing this on actual sparc64 hardware is greatly
appreciated, as there will unavoidably be bugs left.

Many thanks go to Roman Divacky for his upstream work on getting the
sparc64 backend into shape.

MFC after:	1 month
Integrate device-tree upstream files into the build process:
(1) Invoke cpp to bring in files via #include (although the old
    /include/ stuff is supported still).
(2) bring in files from either vendor tree or freebsd-custom files
    when building.
(3) move all dts* files from sys/boot/fdt/dts to
    sys/boot/fdt/dts/${MACHINE} as appropriate.
(4) encode all the magic to do the build in sys/tools/fdt/make_dtb.sh
    so that the different places in the tree use the exact same logic.
(5) switch back to gpl dtc by default. the bsdl one in the tree has
    significant issues not easily addressed by those unfamiliar with
    the code.
Workaround an apparent bug in VMWare Fusion's nested VT support where it
triggers a VM exit with the exit reason of an external interrupt but
without a valid interrupt set in the exit interrupt information.

Tested by:	Michael Dexter
Reviewed by:	neel
MFC after:	1 week
Undo two previous imports which was never done in preparation of doing a
new import.
Redo import of ncurses 5.9 (stripped).
Whitespace fix.
since -F is safe, and an update from 10-HEAD to 10-STABLE is sooo bloody
anoying w/o it..  recommend people use -F too...
ext2fs: use of tab vs spaces.

Consistently use a single tab after a #define as mentioned in style(9).
Use tabs instead of space for indenting.
Fix a typo: "hash_vesion".

No functional change.

MFC after:	3 days
Correct VMware capitalization.

Submitted by:	joeld
Only try to build the static dtb when we're building a static dtb...
Use proper include path for dtc as well as cpp.
Fix syntax errors (missing ;) that bsdl dtc was tolerant of, but gpl
dtc isn't.
Add a script which lists SVN log entries only for changesets
which have files which have been Added or Removed.

This can help identify changesets which should be
mentioned in Release Engineering's release notes.
MFV r262617: ncurses 5.9.
Bump __FreeBSD_version after import of ncurses 5.9.
Remove now dead code.
Compensate previous import with the removed files.
Be paranoid about bit operations here.