Checking if an Integer is an Exact Binary Power

[Nordlöw via Digitalmars-d]

On Saturday, 23 April 2016 at 20:42:25 UTC, Lass Safin wrote:
> CPUID: https://en.wikipedia.org/wiki/CPUID.
> You can check for the presence of a lot of instructions with 
> this instruction.
> However this will only work on x86 and only run-time.

Code you give a complete code example in D, please or point out a 
suitable place in druntime/phobos?