function copysignf( x, y ) {
	return addon( x, y );
}
Returns a single-precision floating-point number with the magnitude of `x` and the sign of `y`.

@private
@param {number} x - number from which to derive a magnitude
@param {number} y - number from which to derive a sign
@returns {number} a single-precision floating-point number

@example
var z = copysignf( -3.0, 10.0 );
// returns 3.0

@example
var z = copysignf( 3.0, -1.0 );
// returns -3.0

@example
var z = copysignf( 1.0, -0.0 );
// returns -1.0

@example
var z = copysignf( -3.0, -0.0 );
// returns -3.0

@example
var z = copysignf( -0.0, 1.0 );
// returns 0.0