/* $DOC$
   $NAME$
      ft_PrtScr()
   $CATEGORY$
      Keyboard/Mouse
   $ONELINER$
      Enable or disable the Print Screen key
   $SYNTAX$
      ft_PrtScr( [ <lSetStat> ] ) -> lCurStat
   $ARGUMENTS$
      <lSetStat> set to .T. will enable the Print Screen key,
      .F. will disable it.  If omitted, leaves status as is.
   $RETURNS$
      The current state: .T. if enabled, .F. if disabled.
   $DESCRIPTION$
      This function is valuable if you have a need to disable the
      printscreen key.  It works by fooling the BIOS into thinking that
      a printscreen is already in progress.  The BIOS will then refuse
      to invoke the printscreen handler.
   $EXAMPLES$
      ft_PrtScr( .F. )       // Disable the printscreen key
      ft_PrtScr( .T. )       // Enable the printscreen key
      MemVar := ft_PrtScr()  // Get the current status
   $SEEALSO$
      ft_CapLock(), ft_Ctrl(), ft_NumLock(), ft_Shift(), ft_Alt()
   $END$
 */