Patch to bfd/aix5ppc-core.c for gdb-6.3 with gcc 4 on AIX5.1

[Nick Clifton]

Hi Rodney,

> So maybe
> 
> The core_hdr() macro is no longer used here because it would
> expand to code relying on gcc's cast-as-lvalue extension, removed in gcc
> 4.0.

I have checked the patch in with this rewording.

Cheers
   Nick