MFC r309412,r316109,r316132:

r309412 (by imp):

dd is currently a bootstrap tool. It really doesn't have any business
being a bootstrap tool. However, for reproducible build output,
FreeBSD added dd status=none because it was otherwise difficult to
suppress the status information, but retain any errors that might
happen. There's no real reason that dd has to be a build tool, other
than we use status=none unconditional. Remove dd from a bootstrap tool
entirely by only using status=none when available. This may also help
efforts to build the system on non-FreeBSD hosts as well.

r316109:

Don't hardcode input files for stage 1/2 bootloaders; use .ALLSRC instead

This is a better pattern to follow when creating the bootloaders and doing
the relevant space checks to make sure that the sizes aren't exceeded (and
thus, copy-pasting is a bit less error prone).

r316132:

Parameterize out 7680 (15 * 512) as BOOT2SIZE, similar to sys/boot/i386/zfsboot/...

This is being done to make it easier to change in the future--this action might be
needed sooner rather than later because of gcc 6.3.0 bailing, stating that there
is negative free space left (deficit) in the boot2 bootloader.

MFC r264400,r265836:

r264400:

NO_MAN= has been deprecated in favor of MAN= for some time, go ahead
and finish the job. ncurses is now the only Makefile in the tree that
uses it since it wasn't a simple mechanical change, and will be
addressed in a future commit.

r265836:

Remove last two NO_MAN= in the tree. In both of these cases, MAN= is
what is needed.

MFC r262613:

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 r262985:

Repair a few minor mismerges from r262261 in the clang-sparc64 project
branch. This is also to minimize differences with upstream.

MFC r264400,r265836:

r264400:

NO_MAN= has been deprecated in favor of MAN= for some time, go ahead
and finish the job. ncurses is now the only Makefile in the tree that
uses it since it wasn't a simple mechanical change, and will be
addressed in a future commit.

r265836:

Remove last two NO_MAN= in the tree. In both of these cases, MAN= is
what is needed.

MFC r262613:

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 r262985:

Repair a few minor mismerges from r262261 in the clang-sparc64 project
branch. This is also to minimize differences with upstream.