src: add using_domains to node_internals

Make it easy to check if domains are in use

src/node.cc

@@ -133,7 +133,7 @@ static bool use_debug_agent = false;
 static bool debug_wait_connect = false;
 static int debug_port=5858;
 static int max_stack_size = 0;
-static bool using_domains = false;
+bool using_domains = false;
 
 // used by C++ modules as well
 bool no_deprecation = false;

src/node_internals.h

@@ -110,6 +110,9 @@ v8::Handle<v8::Value> FromConstructorTemplate(
     v8::Persistent<v8::FunctionTemplate> t,
     const v8::Arguments& args);
 
+// allow for quick domain check
+extern bool using_domains;
+
 } // namespace node
 
 #endif // SRC_NODE_INTERNALS_H_