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)

Modify our boot block to pick an output device, without which boot1 will fail
on G4 machines. On the assumption that most people using FreeBSD on Apple
hardware are not using serial consoles, set boot1's output to screen. This
should be revisited. While here, reduce verbosity of boot1.

Add a simple HFS boot block implementation for booting PowerPC macs. It creates
a small HFS filesystem with a CHRP boot script and an early-stage bootloader
derived from the sparc64 boot block.

Obtained from: sparc64