new kdb patch with disassembler support

Hi,

I grew tired of not being able to disassemble code with kdb. This was really tedious when I was looking at the PAL problems. So I decided to add support for it. It is included in this patch and is based on the BFD code.

Summary of changes:

- upgrade to 2.4-test1

- disassembler support via the id command. Symbol lookups is fully supported. Single stepping now shows code as well. (S.Eranian)

- restructured machine dependent input/output (kdba_io.c). There was way too much code duplication. A side effect is that with 2 consoles (serial+vga) you can now debug from either places. (S.Eranian)

- vastly enhanced command line editing (S.Eranian):
* (CTRL-U/CTRL-C)
* history buffer via (CTRL-P/CTRL-N)
* Enter will redo the last command (that's for David!)

- some code cleanups (David + Stephane)

- updated backtracing support to latest unwind code (D.Mosberger)

The patch is relative to 2.4-test1 + David's 0609 diff.

It is available from the HPLabs web site at:

	ftp://ftp.hpl.hp.com/pub/linux-ia64/kdb-2.4-test1.patch

Enjoy,

Known Issue:
- on serial line the output of certain editing commands like CTRL-U is bogus but the buffer is valid. This is due to some timing problems with the UART which I did not have time to really fix. Anybody with UART understanding can probably fix this in minutes. Patch welcomed !

-Stephane