twClockOn( wT, wL, wColor, lAbsolute )
 ----------------------------------------------------------------------------
     Display a digital clock in text mode.

                     *** NOTE ***

     This routine uses CLOCK.ASM which attaches itself to Interrupt 1C.
     CARE MUST BE TAKEN TO TURN THE CLOCK OFF WHEN LEAVING THE
     APPLICATION, EITHER ON PURPOSE OR IN AN ERROR CONDITION.

       Arguments:

     wT, wL - 'N' Relative window coordinates. Defaults to the top,
                  left corner of the window.

     wColor - 'C' Clipper colour string or attribute.  Defaults to the
                  current window colour.

       Return:

     NIL

       Example:

     twClockOn( 5, 5, "w/b" )