function lnf( x ) {
	return addon( x );
}
Evaluates the natural logarithm of a single-precision floating-point number.

@private
@param {NonNegativeNumber} x - input value
@returns {number} function value

@example
var v = lnf( 4.0 );
// returns ~1.386

@example
var v = lnf( 0.0 );
// returns -Infinity

@example
var v = lnf( Infinity );
// returns Infinity

@example
var v = lnf( NaN );
// returns NaN

@example
var v = lnf( -4.0 );
// returns NaN