Incorporate review comment

Author: kleisauke

emcc.py

@@ -3769,8 +3769,8 @@ def modularize():
 
   # FIXME: https://bugs.webkit.org/show_bug.cgi?id=223533
   src = '''
-%(maybe_async)sfunction(_%(EXPORT_NAME)s) {
-  %(EXPORT_NAME)s = _%(EXPORT_NAME)s || {};
+%(maybe_async)sfunction(config) {
+  var %(EXPORT_NAME)s = config || {};
 
 %(src)s