Add evbmips support for u-boot handling.

Add installboot(8) support for evbarm (and, in the future, other evb*)
boards that use u-boot. A known board database lists boards and their
respective u-boot packages. u-boot packages are discovered at run-time
(in /usr/pkg/share/u-boot, by default). These packages contain board
database overlays that describe u-boot installation procedure that's
specific for that board.

Support this as a native tool and as a host tool. The native tool
will attempt to determine the running board type using OpenFirmware
calls. Host tool and native tool alike may also specify a board type
directly using the "-o board=xxx option" or have installboot(8) determine
the board type from a device tree blob using "-o dtb=/path/to/board.dtb".
A "-o media=xxx" option is provided for boards that have different u-boot
binaries and/or installation procedures for different media types (e.g.
SDMMC, eMMC, or USB).

This is trivial to extend to other evb* platforms that use u-boot, even if
they don't use FDT for autoconfiguration.

branches: 1.11.44;
merge the bouyer-quota2 branch. This adds a new on-disk format
to store disk quota usage and limits, integrated with ffs
metadata. Usage is checked by fsck_ffs (no more quotacheck)
and is covered by the WAPBL journal. Enabled with kernel
option QUOTA2 (added where QUOTA was enabled in kernel config files),
turned on with tunefs(8) on a per-filesystem
basis. mount_mfs(8) can also turn quotas on.

See http://mail-index.netbsd.org/tech-kern/2011/02/19/msg010025.html
for details.

branches: 1.10.2;
Rename Makefile.disklabel to Makefile.nbincludes, as this file has
been used by more than disklabel for years. New name suggestion from
mrg@ .

.include Makefile.disklabel in installboot, so that the
nbinclude/ header files will be installed. Build installboot after
pax, since Makefile.disklabel uses pax to install the headers.

use reachover relative paths in compat include files instead of
symlinking ufs include files into installboot and makefs tool objdirs
reviewed by lukem and thorpej on tech-toolchain

Centralize the definition of the tool name prefix (i.e. "nb") into
bsd.own.mk, as the _TOOL_PREFIX variable.

Make Solaris 8 happy: use ln -f -s instead of ln -fs

branches: 1.5.2;
add -I. to HOST_CPPFLAGS

borrow trick from ../makefs/Makefile to make this more portable for <ufs/...

Add -I../mips-elf2ecoff to take advantage of the host friendly sys/exec_elf.h
that's in that directory. Fixes compile issue on (older source ?) arm
systems noted by Richard Earnshaw.

XXX: arguably a better version of sys/exec_elf.h (and others) should
be in ../compat instead, but that's a problem for another day.

Add shim dev/dec/dec_boot.h (#includes "../../sys/dev/dec/dec_boot.h")
so that we don't rely upon host's <dev/dec/dec_boot.h>

add nbinstallboot