Number of Bits Needed to Represent a Zero-Offset Integer

["Nordlöw" via Digitalmars-d-learn]

On Monday, 19 January 2015 at 13:30:47 UTC, Steven Schveighoffer 
wrote:
> http://dlang.org/phobos/core_bitop.html#.bsr
>
> It's actually an intrinsic, reduces to an instruction. Mind the 
> requirements for 0.

This works for me

https://github.com/nordlow/justd/blob/master/traits_ex.d#L406

:)