Fix x86_64 -mfpmath=387 float_t, double_t (bug 20787) [committed]

[Florian Weimer]

On 11/23/2016 06:57 PM, Joseph Myers wrote:
> Bug 20787 reports that, while float_t and double_t for 32-bit x86
> properly respect -mfpmath=sse, for x86_64 they fail to reflect
> -mfpmath=387, which is valid if unusual and results in FLT_EVAL_METHOD
> being 2.  This patch fixes the definitions to respect
> __FLT_EVAL_METHOD__ in that case, arranging for the test that the
> types correspond with FLT_EVAL_METHOD to be run with both -mfpmath=387
> and -mfpmath=sse.

If I read the patch correctly, this changes the float_t type for those 
(obscure) configurations.  Doesn't this warrant a NEWS entry?

Thanks,
Florian