[PATCH][AArch64] Add inlines for signbit

[Joseph Myers]

On Wed, 15 Apr 2015, Wilco Dijkstra wrote:

> Is there a reason this couldn't be done by default in math.h similar to isgreater (unlike
> __builtin_isinf et al, GCC implements signbit efficiently and correctly).

It is, however, not type-generic in GCC 
<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=36757>, so you'd still need 
to have a macro expansion checking sizeof.

-- 
Joseph S. Myers
joseph@codesourcery.com