add gui_x for sending hex value inside an array to the gui. Not sure if this...

add gui_x for sending hex value inside an array to the gui. Not sure if this is really necessary, but it makes it easy to send a list of open windows for one of the extant interfaces

pd/src/m_pd.h

@@ -675,6 +675,7 @@ EXTERN void gui_start_array(void);
 EXTERN void gui_f(t_float f); /* send a float element in an array */
 EXTERN void gui_i(int i);     /* send an int element in an array */
 EXTERN void gui_s(const char *s); /* send a string element in an array */
+EXTERN void gui_x(long unsigned int i);
 EXTERN void gui_end_array(void);
 EXTERN void gui_end_vmess(void);