RFC: TS 18661-4 floating-point interfaces

[Florian Weimer]

On 12/06/2017 06:44 PM, Joseph Myers wrote:
> exp2m1 exp10[*] exp10m1 logp1[**] log2p1 log10p1 rsqrt compoundn rootn
> pown powr acospi asinpi atanpi atan2pi cospi sinpi tanpi reduc_sum
> reduc_sumabs reduc_subsq reduc_sumprod scaled_prod scaled_prodsum
> scaled_proddiff

R defines and exports sinpi, cospi, tanpi, but apparently with 
compatible definitions.  There is a configure check, so a simple rebuild 
should remove those definitions.

There will be a fair number of build failures due to the addition of 
some of these identifiers under _GNU_SOURCE, but all in all, it looks 
fairly manageable.

Thanks,
Florian