[PowerPC] Fix PR25299, -malign-power vs double array

[Mike Stump]

On Dec 8, 2005, at 5:48 PM, Alan Modra wrote:
> This makes ROUND_TYPE_ALIGN agree with ADJUST_FIELD_ALIGN when the  
> first
> element of a struct is an array of doubles.
>
> OK mainline?

Curious.  I've forwarded this on for more darwin folks to ponder.   
Offhand it isn't perfectly clear to me that we should introduce an  
abi breakage on darwin.  On darwin, gcc defined the abi, and any  
change, if therefore a breakage.  It also isn't perfectly clear to me  
we won't want to so fix the abi.  :-)  Ah, abi issues, so much fun.