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

[Joseph S. Myers]

On Wed, 21 Nov 2012, Roland McGrath wrote:

> We should aim to clean up the code to avoid the warnings while not making
> the generated code worse.

That's the intention of my patch - use memcpy, in an inline function so 
the compiler can see everything and optimize to the same code as for type 
punning as appropriate.

-- 
Joseph S. Myers
joseph@codesourcery.com