ELSEIFNDEF      ELSE With IFNDEF                                    Directive

  ELSEIFNDEF <name>

     This directive is the same as an ELSE followed by an IFNDEF. (IFNDEF
     is satified if the argument is not defined.) It is used to start a
     nested conditional block. For example:

                        IF NUMBER EQ 5
                           add ax,3
                        ELSEIFNDEF NAME
                           add bx,2
                        ELSE
                           add cx,1
                        ENDIF

       Notes:     See ELSEIF and IFNDEF for more information.