Added a notification mechanism for sending messages from

another thread to the mainthread in a safe manner.

This is used for the DNS lookup code, and can also
be used by the signal handler to safely report actions back
to the application mainloop without using global variables.

src/network/backend.c

@@ -141,7 +141,7 @@ int net_backend_process()
 	}
 
 	// Process pending DNS results
-	net_dns_process();
+	// net_dns_process();
 
 	g_backend->handler.backend_process(g_backend->data, res);