* Rich Felker <dalias@libc.org> [2017-09-06 22:32:01 -0400]:
> - missed underflow in fma
>   http://www.openwall.com/lists/musl/2017/03/19/6
>   new fma, depends on a_clz_64
>   http://www.openwall.com/lists/musl/2017/04/23/10
>   [new patch on top of old one submitted, still not ideal
>   but no volatile]

attached latest version, i could not find a simpler solution.