Restrict application of eval so it can only be used in the context of the glo...

src/v8natives.js

Index: src/v8natives.js
===================================================================
--- src/v8natives.js	(revision 754)
+++ src/v8natives.js	(working copy)
@@ -105,6 +105,11 @@
 function GlobalEval(x) {
   if (!IS_STRING(x)) return x;
 
+  if (this !== %GlobalReceiver(global)) {
+    throw $EvalError('The "this" object passed to eval ' + 
+                     'must be the global object from which eval originated');
+  }
+  
   var f = %CompileString(x, 0, true);
   if (!IS_FUNCTION(f)) return f;