- 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 the PowerPC Book-E register definitions used by the remote GDB
protocol.

Obtained from: Juniper Networks, Inc.

Make remote GDB work for AIM processors. For BookE, the kernel
will have a special section, named .PPC.EMB.apuinfo, which will
tell GDB that a BookE processor is targeted and which will
result in GDB using a different register definition. In order
to support remote GDB for BookE, we need the GDB stub in the
kernel look for that section and use the BookE definitions.

Add skeletal support for GDB. In particular gdb_cpu_getreg() needs
implementing to make GDB support usable.