[PATCH] Add nextup and nextdown math functions

[Joseph Myers]

On Fri, 20 May 2016, Florian Weimer wrote:

> Would it make sense to have a file without defaults, and use #if
> USE_AS_NEXTDOWN (instead of #ifdef USE_AS_NEXTDOWN)?

Yes, that's preferred.  But once you deal with correct semantics for 
exceptions, implementing these functions in terms of nextafter seems less 
of a good idea, so macroizing these functions may be harder.

-- 
Joseph S. Myers
joseph@codesourcery.com