Xtt --sync option added to debug Xlib

xtt/exe/rt_xtt/src/xtt_main.cpp

@@ -652,9 +652,14 @@ Xtt::Xtt( int *argc, char **argv[], int *return_sts) :
 	case '-': 
 	  // Possible arg to gtk
 	  if ( strcmp( (*argv)[i], "--display") == 0) {
+	    // Gtk arg with parameter
 	    i++;	    
 	    i_incr = 1;
 	  }
+	  else if ( strcmp( (*argv)[i], "--sync") == 0) {
+	    // Gtk arg without parameter
+	    i_incr = 1;
+	  }	    
 	  break;
 	default:
 	  usage();