Add strong mode.

src/compiler.cc

Index: src/compiler.cc
diff --git a/src/compiler.cc b/src/compiler.cc
index 5ac6353b3f4faea7b8837ca5da1841ed920d6cf3..9aab688c6a0492ecabd546c95969e7168437ce67 100644
--- a/src/compiler.cc
+++ b/src/compiler.cc
@@ -1355,7 +1355,7 @@ Handle<SharedFunctionInfo> Compiler::CompileScript(
     }
     if (FLAG_use_strict) {
       info.SetLanguageMode(
-          static_cast<LanguageMode>(info.language_mode() | STRICT));
+          static_cast<LanguageMode>(info.language_mode() | STRICT_BIT));
     }
 
     result = CompileToplevel(&info);
@@ -1389,7 +1389,7 @@ Handle<SharedFunctionInfo> Compiler::CompileStreamedScript(
 
   if (FLAG_use_strict) {
     info->SetLanguageMode(
-        static_cast<LanguageMode>(info->language_mode() | STRICT));
+        static_cast<LanguageMode>(info->language_mode() | STRICT_BIT));
   }
   // TODO(marja): FLAG_serialize_toplevel is not honoured and won't be; when the
   // real code caching lands, streaming needs to be adapted to use it.