Switch over m68k soffloat build to libc/softfloat.

m68k would previously use softfloat functions contained in libgcc_s.

This change aligns m68k with other platforms built with softfloat.

It is still possible to build the gcc_s softfloat impementation by setting
MKSOFFTFLOAT=yes MKLIBCSOFTFLOAT=no

Addresses PR/59393.

Tidy up how __sigaction14_sigtramp.c is added to SRCS.

The fixuns* come from compiler_rt so softfloat doesn't need to provide them.

Move hardfloat support to its own directory

branches: 1.15.2;
Add genassym / assym.h support

branches: 1.14.6;
Add TLS support for m68k.

branches: 1.13.28;
m68k/Makefile.inc:
- add __mmap.S to SRCS.
- add _lwp_getprivate.S mremap.S to ASM.
sys/Makefile.inc:
- look for __glue.S as well as glue.S.
- introduce a new ASM_MD and set it to "_lwp_getprivate.S mremap.S".
this is used for assembler files that may have non-default
implementations.

now m68k and m68000 mostly build again.

branches: 1.12.10;
G/c KMSRCS and KMINCLUDES now that we have common/lib/libc

Welcome to the new compat layout.

Add support to build the mac68k port with soft-float enabled (i.e., setting
MKSOFTFLOAT=yes). The main purpose of this feature is to let NetBSD work
in machines with the 68040LC chip (those that have the FPU bug).

All the work has been done by Bruce O'Neel <edoneel AT sdf.lonestar.org>,
with some very minor changes by me; the patches were being posted to the
port-mac68k mailing list. It has been tested for a long time by several
users, including me.

I have just verified that regular releases, as well as soft-float ones,
continue to build.

There have been no objections to this patch since I asked for them in July
in the port-mac68k list.

SA_SIGINFO support for m68k (libc)

Enable the libc-provided signal trampoline. The old __sigaction14
entry point has been replaced by the new __sigaction14() which is a
wrapper around the __sigaction_sigtramp system call (which is itself
not directly exposed outside of libc).

No shared library version change is necessary; no new symbols
are exposed outside of libc.

branches: 1.7.12;
Move the bswap functions from libutil to libc (this bups the
minor of libc and the major of libutil). For little-endian architectures
merge the bnswap() assembly versions with nto* and hton* using symbols
aliasing. Use symbol renaming for the bswap function in this case to avoid
namespace pollution.
Declare bswap* in machine/bswap.h, not machine/endian.h. For little-endian
machines, common code for inline macros go in machine/byte_swap.h
Sync libkern with libc.
Adjust #include in kernel sources for machine/bswap.h.

add memmove.S to libkern.

Copy more files to libkern.

Added ashldi3.S, ashrdi3.S, and lshrdi3.S to KMSRCS

have copy-to-libkern copy strcat.S, not strcat.c

New-style RCS ids.

Need for copy-to-libkern-machdep in ../../Makefile