Implement SH backtrace using IA64 version

[Kaz Kojima]

"Joseph S. Myers" <joseph@codesourcery.com> wrote:
> On SH, the default debug/backtrace.c using GCC built-in functions
> doesn't work, but the IA64 implementation works as-is, as on x86_64,
> provided you enable unwind info (which is generally needed for
> reliable backtraces on most architectures nowadays; the SH ABI is
> among those that doesn't allow reliable backtraces just using a frame
> pointer).  This patch accordingly makes SH use the IA64
> implementation, like x86_64.
> 
> (With this patch, it looks like SPARC 32-bit will be the only libc
> architecture using the default debug/backtrace.c.)
> 
> 2011-12-02  Joseph Myers  <joseph@codesourcery.com>
> 
> 	* sysdeps/sh/backtrace.c: New.

Looks fine.  Uli, could you please approve this?

Regards,
	kaz