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

*** 348,358 ****
          { "ip", TIO_ATTR_STR, &termio_info.ti_ip },
          { "clear", TIO_ATTR_STR, &termio_info.ti_clear },
          { "cnorm", TIO_ATTR_STR, &termio_info.ti_cnorm },
          { "nel", TIO_ATTR_STR, &termio_info.ti_nel },
          { "cr", TIO_ATTR_STR, &termio_info.ti_cr },
!         { NULL, NULL, NULL }
  };
  
  /*
   * One-key accelerators.  Some commands are used so frequently as to need
   * single-key equivalents.  termio_accelkeys contains a list of the accelerator
--- 348,358 ----
          { "ip", TIO_ATTR_STR, &termio_info.ti_ip },
          { "clear", TIO_ATTR_STR, &termio_info.ti_clear },
          { "cnorm", TIO_ATTR_STR, &termio_info.ti_cnorm },
          { "nel", TIO_ATTR_STR, &termio_info.ti_nel },
          { "cr", TIO_ATTR_STR, &termio_info.ti_cr },
!         { NULL, 0, NULL }
  };
  
  /*
   * One-key accelerators.  Some commands are used so frequently as to need
   * single-key equivalents.  termio_accelkeys contains a list of the accelerator