polyfill registration for Intl.MessageFormatter strawman

messageformatter.js

(function (root, factory) {
    var MessageFormatter = factory();
    // register in -all- the module systems (at once)
    if (typeof define === 'function' && define.amd) {
        defined('IntlMessageFormatter', MessageFormatter);
    }
    if (typeof exports === 'object') {
        module.exports = MessageFormatter;
    }
    if (root) {
        root.IntlMessageFormatter = MessageFormatter;
    }
})(typeof global !== 'undefined' ? global : this, function() {
    "use strict";
    function MessageFormatter() {
        ...
    }
    ...
    return MessageFormatter;
});

We should not use a name when calling define. AMD, just like ES6 and CJS will support anonymous modules.