[PATCH] PPC atomic.h add compare_exchange_val forms

[Steve Munroe]

Ulrich Drepper writes:

> But this makes one thing obvious: the file must be split.  Please send a
> patch which creates powerpc32/bits and powerpc64/bits files.

I can do that but is this really necessary?

Could you explain your concern and criteria for common vs slit? (is the 
use of #ifdef __powerpc64__ that is bothersome?)

In this case 2 of the 3 macros where common to PPC. I think it is useful 
for Paul and I to keep this file common.