- Copy stable/10@285827 to releng/10.2 in preparation for 10.2-RC1
builds.
- Update newvers.sh to reflect RC1.
- Update __FreeBSD_version to reflect 10.2.
- Update default pkg(8) configuration to use the quarterly branch.[1]

Discussed with: re, portmgr [1]
Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC r277962, r277988, r282661, r282727, r282731, r283013, r283035:

Add support for booting relocatable kernels on PowerPC.

Add code to support loading relocatable kernels at offsets that are
not zero.

Move ubldr text section to the start of the output file, so that when you
create a stripped .bin file from it the entry point is the first byte of
the file. (Will allow "load $addr $file ; go $addr" in u-boot.)

Create a relocatable instance of ubldr for ARM (ubldr.bin).

Re-link ubldr when any of its libraries change.

An ARM kernel can be loaded at any 2MB boundary, make ubldr aware of that.

MFC r257210, r258527: No hardfloat in ubldr, save/restore r9 for api calls.

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

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

When running on armv6, set alignment checking to modulo-4 mode rather
than modulo-8, because clang emits ldrd and strd instructions for
addresses that are only 4-byte aligned

Remove some redundant register loads.

Discussed on: arm@

Initial support of loader(8) for ARM machines running U-Boot.

This uses the common U-Boot support lib (sys/boot/uboot, already used on
FreeBSD/powerpc), and assumes the underlying firmware has the modern API for
stand-alone apps enabled in the config (CONFIG_API).

Only netbooting is supported at the moment.

Obtained from: Marvell, Semihalf