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

*** 197,207 ****
           */
          if (_sp == 1) {
                  if (optind >= argc || argv[optind][0] != '-' ||
                      argv[optind] == NULL || argv[optind][1] == '\0')
                          return (EOF);
!                 else if (strcmp(argv[optind], "--") == NULL) {
                          optind++;
                          return (EOF);
                  }
          }
  
--- 197,207 ----
           */
          if (_sp == 1) {
                  if (optind >= argc || argv[optind][0] != '-' ||
                      argv[optind] == NULL || argv[optind][1] == '\0')
                          return (EOF);
!                 else if (strcmp(argv[optind], "--") == 0) {
                          optind++;
                          return (EOF);
                  }
          }