Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

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

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

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

Remove ifdef PC98.

NOSHARED -> NO_SHARED

Start the dreaded NOFOO -> NO_FOO conversion.

OK'ed by: core

MFi386: revision 1.20 (don't strip kgzldr.o)

MFi386: Factor out -nostdlib and use PROG.

MFi386: Removed -elf and duplicate -ffreestanding.

MFi386: Cleanups to sys/boot makefiles.

MFi386: revision 1.16.

Add ${AFLAGS} to 'as' invocation.

MFi386: revisions 1.13 and 1.14.

Use as's --defsym switch to compensate for the loss of the M4 substitution
of SIOPRT which broke kgzldr and therefore make release.

Pointed out by: murray

MFi386: Remove a.out support.

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

-ffreestanding is the word.
(also resort some CFLAGS such that the more "important" value are first so
they are easier to see)

MFi386: revision 1.8

MFi386: revision 1.7.

Added kgzldr for pc98.
crt.s is based on btx.s.