Fix strict-aliasing warnings from unwind-dw2-fde.c

[Roland McGrath]

> On 11/29/2012 03:24 PM, Roland McGrath wrote:
> > Thanks.  I've replaced the branch with this version (in case it works):
> >
> > 	* sysdeps/powerpc/powerpc64/entry.h (TEXT_START): Define using a
> > 	second, differently-typed declaration, rather than a cast.
> This version works, if you could push it to master I'd appreciate it.

Done.

> Your fix to tst-inet6_rth worked as well.

That one I had tested.