add loose mode to __esModule

lib/babel/transformation/modules/common.js

@@ -20,7 +20,9 @@ CommonJSFormatter.prototype.init = function () {
   scope.rename("module");
 
   if (!this.noInteropRequireImport && this.hasNonDefaultExports) {
-    file.ast.program.body.push(util.template("exports-module-declaration", true));
+    var templateName = "exports-module-declaration";
+    if (this.file.isLoose("es6.modules")) templateName += "-loose";
+    file.ast.program.body.push(util.template(templateName, true));
   }
 };
 

lib/babel/transformation/templates/exports-module-declaration-loose.js

@@ -0,0 +1 @@
+exports.__esModule = true;