gistfile1.txt

// Instead of this

var bar = Object.create(foo); 
extend(bar, {
    sayGoodbye: function() { alert("goodbye from " + this.name); }
});

// why not write the following and provide a Object.create polyfill that supports the second argument?

var bar = Object.create(foo, {
    sayGoodbye: function() { alert("goodbye from " + this.name); }
});

Because the second parameter in your example is not a valid property descriptor