Make all ports use a common disklabel.h with MAXPARTITIONS set to 16.
Only RAW_PART varies between ports.

branches: 1.3.2; 1.3.12;
Add getlabelusesmbr(), as proposed in
http://mail-index.netbsd.org/tech-userlevel/2011/08/25/msg005404.html
This is used by disk tools such as disklabel(8) to dynamically decide is
the undelyling platform uses a disklabel-in-mbr-partition or not
(instead of using a compile-time list of ports).
getlabelusesmbr() reads the sysctl kern.labelusesmbr, takes its value from the
machdep #define LABELUSESMBR.
For evbmips, make LABELUSESMBR 1 if the platform uses pmon
as bootloader, and 0 (the previous value) otherwise.

If cpu_disklabel includes struct dkbad, define __HAVE_DISKLABEL_DKBAD.
This allows use of subr_disk_mbr on all archs. Default to it for
the rump disk component. No functional change for regular kernels.
(The other option would've been to include dkbad in disklabels
everywhere, but arguably this approach has less possible side-effects,
especially given that wedges and related magic will take over the
world any second now).

branches: 1.1.2; 1.1.4; 1.1.6; 1.1.54;
Zaurus Port from OpenBSD by Nonaka Kimihiro
OK gimpy