- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

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

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

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

Fix copy-paste bug.

Finally... Import the latest open-source ZFS version - (SPA) 28.

Few new things available from now on:

- Data deduplication.
- Triple parity RAIDZ (RAIDZ3).
- zfs diff.
- zpool split.
- Snapshot holds.
- zpool import -F. Allows to rewind corrupted pool to earlier
transaction group.
- Possibility to import pool in read-only mode.

MFC after: 1 month

Use mf and not mf.a. The latter doesn't force memory ordering and
applies to sequential memory.

Remove confusing mergeinfo caused by renaming files.

- rename atomic.S and crc32.c to avoid collisions when linking zfs in to the kernel
- update Makefile
- ifdef out acl_{alloc, free}, they aren't used by zfs and conflict with existing in-kernel routines

Forced commit to note that these files were repo copied.

Add my copyright.

Requested by: pjd@

Missing atomic operations for ZFS/ia64.

Submitted by: marcel