function expm1rel( x ) {
	return addon( x );
}
Computes the relative error exponential.

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

@example
var v = expm1rel( 0.0 );
// returns 1.0

@example
var v = expm1rel( 1.0 );
// returns ~1.718

@example
var v = expm1rel( -1.0 );
// returns ~0.632

@example
var v = expm1rel( NaN );
// returns NaN