Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

For consistency, change all 'i386' and MACHINE_ARCH to x86.

Reviewed by: jhb
MFC after: 1 week

Create a seperate ZFS enabled loader.

This adds zfsloader which will be called by zfsboot/gptzfsboot code rather
than the tradional loader. This eliminates the need to set the
LOADER_ZFS_SUPPORT variable in order to get a ZFS enabled loader.

Note however, that you must reinstall your bootcode (zfsboot/gptzfsboot)
in order for the boot process to use the new loader.

New installations will no longer be required to build a ZFS enabled
loader for a working ZFS boot system. Installing zfsboot/gptzfsboot is
sufficient for acknowledging the use of CDDL code and therefore the ZFS
enabled loader.

Based on a previous patch from jhb@

Reviewed by: jhb@
MFC after: 2 weeks