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

*** 478,488 ****
                          return(FALSE);
                  }
  
          ASSERT(len >= BUFSIZ, "BUFFER TOO SMALL", "getsysline", 0);
          for(;;) {
!                 while (getaline(fsystems, buf) != NULL)
                      if ((*buf != '#') && (*buf != ' ') &&
                          (*buf != '\t') && (*buf != '\n')) {
                          (void) _uu_resetlocale(LC_ALL, prev);
                          return(TRUE);
                  }
--- 478,488 ----
                          return(FALSE);
                  }
  
          ASSERT(len >= BUFSIZ, "BUFFER TOO SMALL", "getsysline", 0);
          for(;;) {
!                 while (getaline(fsystems, buf) != 0)
                      if ((*buf != '#') && (*buf != ' ') &&
                          (*buf != '\t') && (*buf != '\n')) {
                          (void) _uu_resetlocale(LC_ALL, prev);
                          return(TRUE);
                  }