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)

Make this directory more regular. Since it is one we control, use the
freebsd-based names for filenames. This allows us to eliminate
almost all of the uses of ${MACHINE_ARCH} here to do special things, and
instead we use it to include filenames. This makes new architectures easier
to support.

Initial gdbserver support for PowerPC.

Obtained from: Juniper Networks, Semihalf