function log1mexp( x ) {
	return addon( x );
}
Computes the natural logarithm of \\( 1-\exp(-|x|) \\).

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

@example
var v = log1mexp( 1.1 );
// returns ~-0.40477

@example
var v = log1mexp( 0.0 );
// returns -Infinity

@example
var v = log1mexp( NaN );
// returns NaN