Clock widget

[<gtk uk2 net>]

I'm trying to get the clock widget to work, to no avail. Here's the
source file:

#include <gtk/gtk.h>
#include "gnome.h"
#include "/usr/include/libgnomeui/gtk-clock.h"

int main(int   argc, char *argv[])
{
GtkWidget *window, *clk;

    gtk_init(&argc, &argv);
    
        window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
    clk = gtk_clock_new(GTK_CLOCK_REALTIME);

  gtk_signal_connect (GTK_OBJECT (window), "destroy", 
		      GTK_SIGNAL_FUNC (gtk_main_quit), 
		      "WM destroy");			
			
    gtk_widget_show (window);			
    gtk_main ();
    
    return(0);
} 
/*********************************************************/
Here's the Makefile:

CC = gcc

zzz: zzz.c 
	$(CC) `gtk-config --cflags`  zzz.c -o zzz `gtk-config --libs`

clean: 
	rm -f *.o zzz

/*********************************************************/

 At compile time I get the following error messages:

/tmp/ccN6oiYy.o: In function `main':
/tmp/ccN6oiYy.o(.text+0x28): undefined reference to `gtk_clock_new'
collect2: ld returned 1 exit status

 What's wrong if gtk-clock.h is precisely what defines gtk_clock
 functions?
I'm using GTK+-1.2.5-2, linux 2.2.12 (RedHat 6.1), gnome 1.0.40.

I would appreciate it if anybody could reply. 
Thanks,

Henry