[rfc] Improve NetBSD/i386 signal trampoline detection

[Mark Kettenis]

> From: Nick Hudson <nick.hudson@dsl.pipex.com>
> Date: Thu, 18 Oct 2007 21:20:18 +0100
>
> 	* i386nbsd-tdep.c: Include "trad-frame.h" and "tramp-frame.h"
> 	(sigtramp_retcode, i386nbsd_sigtramp_offset, i386nbsd_sigtramp_p):
> 	Remove
> 	(i386nbsd_mc_reg_offset): New array.
> 	(i386nbsd_sigtramp_cache_init): New function.
> 	(i386nbsd_sigtramp_sc16, i386nbsd_sigtramp_sc2, i386nbsd_sigtramp_si2)
> 	(i386nbsd_sigtramp_si31, i386nbsd_sigtramp_si4): New signal trampoline
> 	frame descriptions.
> 	(i386nbsd_init_abi): Override ABI sigcontext defaults and register
> 	new signal frame unwinders
> 	* Makefile.in (i386nbsd-tdep.o): Update dependencies.
> 	* tramp-frame.h (struct tramp_frame): Allow for 48 instructions

I've comitted this now (sorry for the delay), with a small fix to make
the prototype for i386nbsd_sigtramp_cache_init not start in column
zero.

Daniel, I think that makes Nick qualify for "Write After Approval".
Can you set him up for that?