Since the C standard allows for intermediate floating results to contain
more precision bits than the data type expects, but (kind of obviously)
does not allow such values to be stored in memory, expecting the value
returned from strtod() (an intermediate result) to be identical (that is,
equal) to a stored value is incorrect.

So instead go back to checking that the two numbers are very very close.
See comments added to the test for more explanation.

(kre)