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)

Added the IPLware 3.33 support.
- Added magic numbers to pretend the NEC original program version
2.70.
- Added string display routine with Shift-JIS code support.
- Added three nop instructions at start1 in start.s since the
installaer of the IPLware put 'call $0x09ab' instruction.
- Put the near return instruction at 0x9ab in selector.s.

Since the Shit-JIS display routine must be located at 0x1243, the
linker script file (ldscript) is applied.