Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC r267355:
Add UUIDs for DragonFlyBSD's partition types.

MFC r267356:
Add DragonFlyBSD's Hammer FS types and type names.

MFC r267357:
Add aliases for DragonFlyBSD's partition types.

MFC r267358:
Allow dumping to DragonFlyBSD's swap partition.

MFC r267359:
Add disklabel64 support to GEOM_PART class.

This partitioning scheme is used in DragonFlyBSD. It is similar to
BSD disklabel, but has the following improvements:
* metadata has own dedicated place and isn't accessible through partitions;
* all offsets are 64-bit;
* supports 16 partitions by default (has reserved place for more);
* has reserved place for backup label (but not yet implemented);
* has UUIDs for partitions and partition types;

MFC r267360:
Add disklabel64 support

Relnotes: yes

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Connect geom_part_ldm module to the build.

MFC after: 1 month

Add the EBR scheme. The EBR scheme supports the Extended Boot Records
found inside extended partitions and used to create logical partitions.
At this time write/modify support is not (yet) present.
The EBR and MBR schemes both check the parent scheme. The MBR will
back-off when nested under another MBR, whereas the EBR only nests
under a MBR.

Add support for PC-9800 partition tables.

Instead of making a single geom_part.ko module, make a module
for each partitioning scheme. The gpart code is currently non-
optional.

Add geom_part module.