IE8 does not support Object.defineProperty on non-DOM objects

(see http://stackoverflow.com/questions/3830800/object-defineproperty-in-es5)

lib/util.js

@@ -103,6 +103,8 @@ exports.defineSecureProp = function( obj, prop, value )
         obj[ prop ] = value;
     }
     else
+    {
+        try
         {
             Object.defineProperty( obj, prop,
             {
@@ -113,6 +115,12 @@ exports.defineSecureProp = function( obj, prop, value )
                 configurable: false,
             });
         }
+        catch ( e )
+        {
+            // if there's an error (ehem, IE8), fall back
+            obj[ prop ] = value;
+        }
+    }
 }