illumos gate

Build errors with gcc 10:

    ../../common/io/comstar/lu/stmf_sbd/sbd.c: In function 'sbd_modify_lu':
    ../../common/io/comstar/lu/stmf_sbd/sbd.c:2684:15: error: array subscript 8 is above array bounds
    of 'char[8]' [-Werror=array-bounds]
     2684 |   mlu->mlu_buf[struct_sz - sizeof (*mlu) + 8 - 1] = 0;
          |   ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    In file included from ../../common/io/comstar/lu/stmf_sbd/sbd.c:49:
    ../../common/sys/stmf_sbd_ioctl.h:176:8: note: while referencing 'mlu_buf'
      176 |  char  mlu_buf[8]; /* can be more than 8 */
          |        ^~~~~~~
    ../../common/io/comstar/lu/stmf_sbd/sbd.c: In function 'sbd_set_global_props':
    ../../common/io/comstar/lu/stmf_sbd/sbd.c:2911:15: error: array subscript 8 is above array bounds
    of 'char[8]' [-Werror=array-bounds]
     2911 |   mlu->mlu_buf[struct_sz - sizeof (*mlu) + 8 - 1] = 0;
          |   ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    In file included from ../../common/io/comstar/lu/stmf_sbd/sbd.c:49:
    ../../common/sys/stmf_sbd_ioctl.h:138:8: note: while referencing 'mlu_buf'
      138 |  char  mlu_buf[8]; /* likely more than 8 */
          |        ^~~~~~~
    cc1: all warnings being treated as errors

gcc really oes not like us, when we have fixed size array and attempt to access it past array end...