why does RAND_add() take "randomness" as a "double"?

[Ken Goldman]

On 5/21/2019 9:48 PM, Paul Dale wrote:
> Double makes sense.  Entropy is often estimated as a real value.
> 

Having a human readable calculation using floating point doesn't (to me) 
mean that an API argument has to be a double.

 From what I see in the code, the parameter 'double entropy' is used
to increment a value that eventually reaches # define ENTROPY_NEEDED 32.

Couldn't the number have been an unsigned long?  If more precision was 
needed, make the units 1/64k and make ENTROPY_NEEDED 32 * 64k.  It's a 
bit more work for the caller, but removes the (perhaps only) place 
floating point is needed.