Reinstate INSTALL kernel for embedded ramdisk installs.

Reasons being:
- INSTALL is GENERIC with an embedded ramdisk, and as such, can benefit from
features included within.
- INSTALL_FLOPPY has its own config(5) file, and is tailored for "small"
floppy images; it misses features/drivers that could be needed to boot
in a decent environment for recent x86 machines (like ACPI)
- makes it closer to floppies distrib available for amd64

While here, comment out INSTALL_FLOPPY and bootfloppy-big image build. NetBSD
does not use the 3.6MiB image for El Torito cdroms anymore.

Remove the FLOPPYMAX limit; i386 needs 4 floppies now. Modify boot.cfg and
release/contents to reflect reality.

See http://mail-index.netbsd.org/port-i386/2011/02/08/msg002307.html

No comments, no objections.

branches: 1.22.4;
avoid full path to boot.cfg file when building amd64 boot floppy
share code with i386

branches: 1.21.2;
Put boot.cfg for bootfloppy into ustarfs without path
so that bootloader can load it properly.

Put a boot menu on the amd64+i386 boot floppies. Not used yet because
the ustar loader seems to have the menu code if'd out.

branches: 1.19.20; 1.19.22;
Prepare creation of boot CDs:

* Move files in distrib/i386:

floppies/instkernel/Makefile -> instkernel/Makefile
floppies/ramdisk-big/Makefile -> ramdisks/ramdisk-big/Makefile
floppies/ramdisk-big/disktab.preinstall -> ramdisks/ramdisk-big/disktab.preinstall
floppies/ramdisk-big/list -> ramdisks/ramdisk-big/list
floppies/ramdisk-big/list.inet6 -> ramdisks/ramdisk-big/list.inet6
floppies/ramdisk-rescuetiny/Makefile -> ramdisks/ramdisk-rescuetiny/Makefile
floppies/ramdisk-rescuetiny/list -> ramdisks/ramdisk-rescuetiny/list
floppies/ramdisk-small/Makefile -> ramdisks/ramdisk-small/Makefile
floppies/ramdisk-small/list -> ramdisks/ramdisk-small/list
floppies/ramdisk-tiny/Makefile -> ramdisks/ramdisk-tiny/Makefile
floppies/ramdisk-tiny/list -> ramdisks/ramdisk-tiny/list
floppies/common/Makefile.ramdisk -> ramdisks/common/Makefile.ramdisk
floppies/common/dot.profile -> ramdisks/common/dot.profile
floppies/common/list.ramdisk -> ramdisks/common/list.ramdisk
floppies/common/termcap.mini -> ramdisks/common/termcap.mini

* Adjust paths

Pad all floppy images to the floppy size.
Requested by Jason Thorpe in [port-i386/23785]

Overhaul MBR handling (part 1):

<sys/bootblock.h>:
* Added definitions for the Master Boot Record (MBR) used by
a variety of systems (primarily i386), including the format
of the BIOS Parameter Block (BPB).
This information was cribbed from a variety of sources
including <sys/disklabel_mbr.h> which this is a superset of.

As part of this, some data structure elements and #defines
were renamed to be more "namespace friendly" and consistent
with other bootblocks and MBR documentation.
Update all uses of the old names to the new names.

<sys/disklabel_mbr.h>:
* Deprecated in favor of <sys/bootblock.h> (the latter is more
"host tool" friendly).

amd64 & i386:
* Renamed /usr/mdec/bootxx_dosfs to /usr/mdec/bootxx_msdos, to
be consistent with the naming convention of the msdosfs tools.

* Removed /usr/mdec/bootxx_ufs, as it's equivalent to bootxx_ffsv1
and it's confusing to have two functionally equivalent bootblocks,
especially given that "ufs" has multiple meanings (it could be
a synonym for "ffs", or the group of ffs/lfs/ext2fs file systems).

* Rework pbr.S (the first sector of bootxx_*):
+ Ensure that BPB (bytes 11..89) and the partition table
(bytes 446..509) do not contain code.
+ Add support for booting from FAT partitions if BOOT_FROM_FAT
is defined. (Only set for bootxx_msdos).
+ Remove "dummy" partition 3; if people want to installboot(8)
these to the start of the disk they can use fdisk(8) to
create a real MBR partition table...
+ Compile with TERSE_ERROR so it fits because of the above.
Whilst this is less user friendly, I feel it's important
to have a valid partition table and BPB in the MBR/PBR.

* Renamed /usr/mdec/biosboot to /usr/mdec/boot, to be consistent
with other platforms.

* Enable SUPPORT_DOSFS in /usr/mdec/boot (stage2), so that
we can boot off FAT partitions.

* Crank version of /usr/mdec/boot to 3.1, and fix some of the other
entries in the version file.

installboot(8) (i386):
* Read the existing MBR of the filesystem and retain the BIOS
Parameter Block (BPB) in bytes 11..89 and the MBR partition
table in bytes 446..509. (Previously installboot(8) would
trash those two sections of the MBR.)

mbrlabel(8):
* Use sys/lib/libkern/xlat_mbr_fstype.c instead of homegrown code
to map the MBR partition type to the NetBSD disklabel type.


Test built "make release" for i386, and new bootblocks verified to work
(even off FAT!).

Use ${TOOL_INSTALLBOOT} - it does work on ustarfs filesytems.
Pass correct option to installboot for bootfloppy-com (serial bootfloppy).

Switch boot floppies to 'new' i386 bootcode.

Default FLOPPYMAX to 1 for i386 floppies, so the build will fail if an
image accidentally grows past 1 floppy and we didn't know about it.

Merge kernel-ramdisk & kernel-rescue into instkernel, now that
../../common/Makefile.mdset supports building multiple copies of the
same kernel (as long as they're to separate filenames).
Now there's no need to set FLOPPYKERNDIR, as it now defaults to instkernel.

always set FLOPPYMETAFILE if FLOPPYSIZE!=2880

- add support for [-s suffix] to buildfloppies.sh (defaults to "",
rather than the previous ".fs").
- add support for (optional) FLOPPYSUFFIX in Makefile.tarfloppy, and
use appropriately
- remove (now unnecessary) custom release targets in alpha/instkernel/*

yet another distrib overhaul:
- move guts of distrib/Makefile.inc to distrib/common/Makefile.distrib
(fixes problem caused by implicit include of ../Makefile.inc in certain
submake conditions triggered by makefiles not yet in tree)
- removed mkdir of ${RELEASEDIR}/*; rely upon "snap_pre" target of
etc/Makefile to create all the release directories
- renamed RELINSTALL to RELEASE_INSTALL
- renamed FLOPPYINSTDIR to FLOPPY_RELEASEDIR
- renamed MDSETDIR to MDSET_RELEASEDIR
- removed ITARGET
- move release target from top level to appropriate subdirectory
- ensure release target has correct depends
- replace miniroot's IMAGE_MD_POST with common/Makefile.image IMAGEPOSTBUILD
- Makefile.image: add realall: ${IMAGE}

replace _SRC_TOP_ with NETBSDSRCDIR, since the latter is the "public" version

Migrate MI-shareable stuff to distrib/common/Makefile.tarfloppy.

- Convert to using distrib/common/buildfloppies.sh, which can build both
single and multi-volume floppies in better fashion that the crufty
shell commands in the various Makefiles.
- Move fdset* -> bootfloppy*, as that's more consistent

use ${RELINSTALL} instead of cp -p

Yet Another Cleanup:
- factor more stuff into common/Makefile.*
- use NDWO makefile layout
- don't always rebuild bootfloppy-* and fdset-* stuff. (mmm, dependencies)
- add .WAIT sync in top level Makefile

We need bsd.sys.mk to get ${STRIP} when USETOOLS is not set.

minor whitespace cleanup

add check_RELEASEDIR to targets that require RELEASEDIR to be set

Major overhaul, to enable unprivileged (cross) building, removing the
requirement to build as root on a system with vnconfig.


Use ${KERNSRCDIR} and ${_SRC_TOP_} where appropriate

Remove now-obsolete:
list2sh.awk runlist.sh bootfloppy-common/list

Bootfloppy-*/Makefile: don't need to set DISKTYPE or BLOCK8K any more

Rename bootfloppy-common/Makefile.inc to common/Makefile.bootfloppy
and fdset-common/Makefile.inc to common/Makefile.fdset
This uses makefs instead of vnconfig and disklabel, thus removing the
need for root privileges to build these floppies..

Add common/Makefile.ramdisk, to simplify ramdisk-*/Makefile.
Uses shared ${_SRC_TOP_}/distrib/common/Makefile.crunch and
${_SRC_TOP_}/distrib/common/Makefile.image to even further simply things.

Migrate ramdisk-*/dot.profile to a shared common/dot.profile, which
detects whether it's an install or rescue profile based on the existance
of /sysinst. Remove /dev generation code as init(8) now does that for us.

Migrate common parts of */list to a shared common/list.ramdisk.
Convert ramdisk-*/list to new format used by distrib/common/parselist.awk
Don't bother running pwd_mkdb now that libhack's getpwent parses
/etc/master.passwd instead of /etc/passwd.

Migrate ramdisk-*/mtree.conf to a shared common/mtree.conf, which is now a
new full-path-style specfile.

Remove ramdisk-*/ramdiskbin.conf as it's now automatically generated
from ramdisk-*/list by parselist.awk.

Migrate ramdisk-*/termcap.mini to a shared common/termcap.mini.

Remove unused ramdisk-{small,tiny}/disktab.preinstall.

Use .for loops in kernel-*/Makefile to simply defining mostly-duplicated
targets.

ramdisk-*/Makefile: convert to using common/Makefile.ramdisk

Remove unused ramdisk-*/dot.hdprofile.