lodash: Add support for more AMD build optimizers and allow aliasing as the "underscore" module. [jddalton]

Former-commit-id: 6b3fa45d19f6a55aa7565bcb4d9221f6f159e9c9

lodash.js

@@ -2796,23 +2796,20 @@
     else {
       freeExports._ = lodash;
     }
-  } else {
-    // in a browser or Rhino
+  }
+  // in a browser or Rhino
+  else {
+    // Expose Lo-Dash to the global object even when an AMD loader is present in
+    // case Lo-Dash was injected by a third-party script and not intended to be
+    // loaded as a module. The global assignment can be reverted in the Lo-Dash
+    // module via its `noConflict()` method.
     window._ = lodash;
 
-    // Expose Lo-Dash as an AMD module, but only for AMD loaders that understand
-    // the issues with loading multiple versions of Lo-Dash in a page that all
-    // might call `define()`. The loader will indicate they have special
-    // allowances for multiple Lo-Dash versions by specifying
-    // `define.amd.lodash=true`. Register as a named module, since Lo-Dash can
-    // be concatenated with other files that may use `define()`, but not use a
-    // proper concatenation script that understands anonymous AMD modules.
-    // Lowercase `lodash` is used because AMD module names are derived from
-    // file names, and Lo-Dash is normally delivered in a lowercase file name.
-    // Do this after assigning Lo-Dash the global so that if an AMD module wants
-    // to call `noConflict()` to hide this version of Lo-Dash, it will work.
-    if (typeof define == 'function' && typeof define.amd == 'object' && define.amd && define.amd.lodash) {
-      define('lodash', function() {
+    // some AMD build optimizers, like r.js, check for specific condition patterns like the following:
+    if (typeof define == 'function' && typeof define.amd == 'object' && define.amd) {
+      // define as an anonymous module so, through path mapping, it can be
+      // referenced as the "underscore" module
+      define(function() {
         return lodash;
       });
     }