RFA: fix for 17961 (ppc vectors)

[Geoffrey Keating]

Aldy Hernandez <aldyh@redhat.com> writes:

>   #define ROUND_TYPE_ALIGN(TYPE, COMPUTED, SPECIFIED)			\
> ! 	((TARGET_ALTIVEC  && TREE_CODE (TYPE) == VECTOR_TYPE		\
> ! 	  && ALTIVEC_VECTOR_MODE (TYPE_MODE (TYPE)))			\

- TARGET_ALTIVEC shouldn't be used here, it should be TARGET_ALTIVEC_ABI,
  since this affects the ABI (I know it was like this before your patch,
  but I think that was part of the problem).
- Doesn't this change alter the ABI?  I guess it doesn't matter that much
  for this relatively rare case.