stand: Make pc98 build

This is a direct commit to stable/11 due to pc98 removal from head.

Several improvements in head that were MFC'd left the pc98 build broken in
stable/11. Massage the pc98 bits to get it to at least build.

MFC r325834,r325997,326502: Move sys/boot to stand/

This is effectively a direct commit to stable/11, due to differences between
stable/11 and head. Changes to DTS in sys/boot/fdt/dts were often
accompanied by kernel changes. Many of these were also risc-v updates that
likely had many more dependencies to MFC.

Because of this, sys/boot/fdt/dts remains as-is while everything else in
sys/boot relocates to stand/.

r325834: Move sys/boot to stand. Fix all references to new location

r325997: Remove empty directories.

r326502: Document the sys/boot -> stand move in hier.7 and the top-level README.

MFC r303555,r303556,r303936,r303962,r304317,r304532,r305026,r305107,r305132,
r305178,r305353,r305814,r306159,r306380,r306504: Loader fixes, 2016q3

r303555: bcache should support reads shorter than sector size

r303556: Improve boot loader quote parsing

r303936: Add kernel environment variables under smbios.system

r303962: Add the missing space between .asciz directive and opening quote
for some lines with #ifdef BTXLDR_VERBOSE/#endif

r304317: boot1.efi Free() should check for NULL to provide consistent
behavior

r304532: Replace sprintf -> snprintf for command_errbuf provisioned from
dynamic content.

r305026: Emulate efi_cons_poll when WaitForKey is not available

r305107: Create a hook 'post-initialize' for people that want to define
something to read in .conf files after all other .conf files for the purpose
of overriding.

r305132: Remove accidentally committed stray comment.

r305178: bd_int13probe() should check extended info if sector info is bad

r305353: Don't use -N to set the OMAGIC with data and text writeable and
data not page aligned.

r305814: ufsread: Do not cast struct direct from void *

r306159: Consistently declare getsecs(void) with proper return type and void
when no arguments are present.

r306380: loader command interpreter should reset command_errmsg

r306504: Fix a cluster of bugs in list EFI environment variables

PR: 204602, 211958, 211958
Relnotes: yes ("Improve boot loader quote parsing")

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Implement (ACFLAGS|CFLAGS|CXXFLAGS).SRC globally.

Sponsored by: EMC / Isilon Storage Division

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.

Reduce diffs against i386.

MFi386: improve argument passing via btxldr

use related definitions in i386 bootargs.h

Reviewed by: nyan, jhb
MFC after: 1 month

Define several extra macros in bsd.sys.mk and sys/conf/kern.pre.mk, to
get rid of testing explicitly for clang (using ${CC:T:Mclang}) in
individual Makefiles.

Instead, use the following extra macros, for use with clang:
- NO_WERROR.clang (disables -Werror)
- NO_WCAST_ALIGN.clang (disables -Wcast-align)
- NO_WFORMAT.clang (disables -Wformat and friends)
- CLANG_NO_IAS (disables integrated assembler)
- CLANG_OPT_SMALL (adds flags for extra small size optimizations)

As a side effect, this enables setting CC/CXX/CPP in src.conf instead of
make.conf! For clang, use the following:

CC=clang
CXX=clang++
CPP=clang-cpp

MFC after: 2 weeks

Upgrade our copy of llvm/clang to r126079, from upstream's trunk.

This contains many improvements, primarily better C++ support, an
integrated assembler for x86 and support for -pg.

Use -Wl,-N instead of the undocumented -N option for GCC.

GCC forwards the -N flag directly to ld. This flag is not documented and
not supported by (for example) Clang. Just use -Wl,-N.

Submitted by: Pawel Worach

Remove ifdef PC98.

Start the dreaded NOFOO -> NO_FOO conversion.

OK'ed by: core

MFi386: revisions from 1.15 to 1.17.

MFi386: Use C (and CPP) style comments for assembler-with-cpp
sources, for lines that start with a comment.

MFi386: Get rid of unnecessary use of m4(1) by using cpp(1) instead.

Repocopied by: joe

MFi386: Factor out -nostdlib and use PROG.

MFi386: Cleanups to sys/boot makefiles.

MFi386: revision 1.13.

Initiate deorbit burn for the i386-only a.out related support. Moves are
under way to move the remnants of the a.out toolchain to ports. As the
comment in src/Makefile said, this stuff is deprecated and one should not
expect this to remain beyond 4.0-REL. It has already lasted WAY beyond
that.

Notable exceptions:
gcc - I have not touched the a.out generation stuff there.
ldd/ldconfig - still have some code to interface with a.out rtld.
old as/ld/etc - I have not removed these yet, pending their move to ports.
some includes - necessary for ldd/ldconfig for now.

Tested on: i386 (extensively), alpha

Sync with the following changes.

sys/boot/i386/btx/btx/Makefile 1.8
sys/boot/i386/btx/btx/btx.s 1.16 and 1.17
sys/boot/i386/btx/btxldr/btxldr.s 1.10
sys/boot/i386/loader/Makefile 1.45

Synced with following files:
src/sys/boot/i386/Makefile.inc 1.1
src/sys/boot/i386/btx/btx/btx.s 1.15
src/sys/boot/i386/btx/btxldr/Makefile 1.8
src/sys/boot/i386/btx/btxldr/btxldr.s 1.9
src/sys/boot/i386/libi386/biosdisk.c 1.29
src/sys/boot/i386/loader/Makefile 1.42
src/sys/boot/i386/loader/main.c 1.18
(entry point address of loader was not changed.)

Reviewed by: nyan

Blank out the twiddly thing when outputting the ``BTX loader'' message.

$Id$ -> $FreeBSD$

PC98 version of new boot loader. Because boot2 has not yet ported,
files in boot2 directory are copies from legacy biosboot.

Submitted by: IMAI Takeshi <take-i@ceres.dti.ne.jp>