Enable optimization of top-level code.

src/ia32/lithium-ia32.cc

Index: src/ia32/lithium-ia32.cc
===================================================================
--- src/ia32/lithium-ia32.cc	(revision 10686)
+++ src/ia32/lithium-ia32.cc	(working copy)
@@ -1150,6 +1150,12 @@
 }
 
 
+LInstruction* LChunkBuilder::DoDeclareGlobals(HDeclareGlobals* instr) {
+  LOperand* context = UseFixed(instr->context(), esi);
+  return MarkAsCall(new(zone()) LDeclareGlobals(context), instr);
+}
+
+
 LInstruction* LChunkBuilder::DoGlobalObject(HGlobalObject* instr) {
   LOperand* context = UseRegisterAtStart(instr->value());
   return DefineAsRegister(new(zone()) LGlobalObject(context));