Only use the ldscript for the RAMDISK kernel for now.

use -ffunction-sections -fdata-sections --gc-sections with an ldscript
that keeps _start. This deletes all unused code and shrinks the RAMDISK
kernel enough to be able to boot again:

-rwxr-xr-x 1 root src 2519436 Aug 30 06:38 RAMDISK.1/netbsd*
-rwxr-xr-x 1 root src 2104440 Aug 30 07:41 RAMDISK/netbsd*

text data bss dec hex filename
1525412 686252 63552 2275216 22b790 RAMDISK.1/netbsd
1098524 686400 67008 1851932 1c421c RAMDISK/netbsd

Kernel without -fno-omit-frame-pointer works fine now, both for GCC8 and 9.
Not sure which commit ``fixed'' the problem although...

don't warn about array bounds for dodgy diagnostic code.
fixes gcc9 builds.

Compile sun2 kernel with -fno-omit-frame-pointer for GCC8 as a work
around for reproducible kernel freezes just after ``Starting postfix.'',
where I cannot even enter DDB nor obtain crash dump.

I still haven't figured out why. Possibly something wrong with -Os
optimization level for GCC/m68k, cf.,
http://mail-index.netbsd.org/port-sun3/2020/07/19/msg000166.html

- Determine KERN_AS automatically depending on whether OPT_MODULAR is
set or not, in the same way as libcompat.

- Specify OPT_MODULAR in the port Makefile instead of KERN_AS.

Now, KERN_AS=library is used for kernels without module(7) for all ports.

OK christos

No need to specify COMPAT_AS anymore.
Now, it is automatically determined from OPT_MODULAR.

branches: 1.22.2;
Remove more unused functions with COMPAT_AS=library

branches: 1.21.2;
sun2/sun3:
- build libkern as an archive for non modular builds. from maya@
sun3:
- cut down GENERIC a bunch to bring below 2MB.
- reduce UBC_NWINS, MAXEXEC, and PAGER_MAP_DEFAULT_SIZE to recover
enough lost VA to actually run basic tests.

branches: 1.20.48;
Switch remaining platforms to modern CPP for assembler.

branches: 1.19.32; 1.19.38; 1.19.40;
Missing assym.h dependency.

branches: 1.18.50; 1.18.56; 1.18.64;
merge ktrace-lwp.

branches: 1.17.2;
s/GENASSYM/GENASSYM_CONF/ so we can use "GENASSYM" as the program name.

Add the %MAKEOPTIONSAPPEND token at the end of the file, after the
common Makefile.kern.inc has been included.

branches: 1.15.6; 1.15.10;
The traditional C preprocessor is fixed in GCC 3.3 now, so no need
to skip -traditional-cpp for HAVE_GCC3.

merge the 12 copies of vm_machdep.c on the m68k platforms.
clean up some other stuff along the way, including:
- use m68k/cacheops.*, remove duplicates from cpu.h.
- centralize a few declarations in (all the copies of) cpu.h.
- define M68K_VAC on platforms which have a VAC.
- switch the sun platforms to the (now common) proc_trampoline().
- do the phys_map thang on the sun platforms too, no reason not to.

Don't use -traditional-cpp if HAVE_GCC3.

branches: 1.12.8;
Clean up CPP flags.

Abstract out a large chunk of the kernel build machinery so that new
build features (such as ross's DEBUGLIST) can easily be applied to all
ports. This should reduce the complexity of each port's kernel
Makefile considerably.

In kernel config files, now mention the options SCSI_OLD_NOINQUIRY,
NFS_V2_ONLY, and VNODE_OP_NOINLINE, commented out as appropriate
for each configuration.
Convert to use genassym.cf and genassym.sh, as other ports do.

cleanup:
options SPACE TAB
makeoptions TAB
psuedo-device TAB
remove trailing whitespace
replace multiple spaces -> tabs
options "FOO" -> options FOO
options "FOO=bar" -> options FOO=bar
options "FOO=\"bar\"" -> options FOO="\"bar\""

- pull in opt_kgdb.h where necessary
- replace opt_kgdb_machdep.h with opt_kgdb.h
- defparam opt_kgdb.h:
KGDB_DEV KGDB_DEVNAME KGDB_DEVADDR KGDB_DEVRATE KGDB_DEVMODE
- move from opt_ddbparam.h to opt_ddb.h:
DDB_FROMCONSOLE DDB_ONPANIC DDB_HISTORY_SIZE DDB_BREAK_CHAR SYMTAB_SPACE
- replace KGDBDEV with KGDB_DEV
- replace KGDBADDR with KGDB_DEVADDR
- replace KGDBMODE with KGDB_DEVMODE
- replace KGDBRATE with KGDB_DEVRATE
- use `9600' instead of `0x2580' for 9600 baud rate
- use correct quotes for options KGDB_DEVNAME="\"com\""
- use correct quotes for options KGDB_DEV="17*256+0"
- remove unnecessary dependancy on Makefile for kgdb_stub.o
- minor whitespace cleanup

branches: 1.7.2;
Change defaults for kernel compiles. Default all to USETOOLS?=no and have
the etc Makefile override that by putting USETOOLS into $.MAKEOVERRIDES
This way the default for kernel compiles is still to use the installed
toolchain instead of depending on $TOOLDIR. $TOOLDIR can be used by
simply adding USETOOLS=yes to the command line as usual.

Adjust each ports template to set the default no setting and also pull in
bsd.own.mk if they weren't already to ensure they'll build correctly
with the new toolchain setup.

branches: 1.6.2;
Set MACHINE_ARCH explicitly in Makefiles for which it is constant.
Also, since config(8) now explcitly sets MACHINE, there is no need
to do it here in the Makefile.

Added -D__SVR4_ABI__ to XDEFS. Without it, m68k libkern assembly
functions don't return pointer values in %a0.

branches: 1.4.2;
Updated for ELF support.

define _KERNEL_OPT as well as _KERNEL. we will use this in the future to
get kernel "opt_foo.h" headers, rather than _KERNEL && !_LKM.

branches: 1.2.2;
A successful compile is near.

Added.