5218 posix definition of NULL
correct unistd.h and iso/stddef_iso.h
update gate source affected

*** 551,561 ****
          }
  
          /* process the arguments */
  
          for (i = mac = 0;
!             (av[i] != (char *)NULL) && (av[i][0] != (char)NULL);
              i++) {
                  if (!fflag && av[i][0] == '-') {
                          /*
                           *  If there is not already a "--" argument specified,
                           *  and the argument starts with '-' but does not
--- 551,561 ----
          }
  
          /* process the arguments */
  
          for (i = mac = 0;
!             (av[i] != NULL) && (av[i][0] != '\0');
              i++) {
                  if (!fflag && av[i][0] == '-') {
                          /*
                           *  If there is not already a "--" argument specified,
                           *  and the argument starts with '-' but does not