illumos gate

Build errors with gcc 9:

    ../../common/io/aggr/aggr_ctl.c: In function 'aggr_ioc_modify':
    ../../common/io/aggr/aggr_ctl.c:72:10: error: 'lacp_timer' may be used uninitialized in this function [-Werror=maybe-uninitialized]
       72 |  return (aggr_grp_modify(modify_arg->lu_linkid, modify_mask, policy,
          |         ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
       73 |      mac_fixed, mac_addr, lacp_mode, lacp_timer));
          |      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    ../../common/io/aggr/aggr_ctl.c:72:10: error: 'lacp_mode' may be used uninitialized in this function [-Werror=maybe-uninitialized]
    ../../common/io/aggr/aggr_ctl.c:72:10: error: 'mac_fixed' may be used uninitialized in this function [-Werror=maybe-uninitialized]
    ../../common/io/aggr/aggr_ctl.c:72:10: error: 'policy' may be used uninitialized in this function [-Werror=maybe-uninitialized]
    ../../common/io/aggr/aggr_ctl.c: In function 'aggr_ioc_add_remove':
    ../../common/io/aggr/aggr_ctl.c:242:9: error: 'rc' may be used uninitialized in this function [-Werror=maybe-uninitialized]
      242 |  return (rc);
          |         ^

    ../../common/io/aggr/aggr_grp.c: In function 'aggr_add_pseudo_rx_group':
    ../../common/io/aggr/aggr_grp.c:743:22: error: 'i' may be used uninitialized in this function [-Werror=maybe-uninitialized]
      743 |  uint_t   hw_rh_cnt, i;
          |                      ^
    ../../common/io/aggr/aggr_grp.c:792:2: error: 'addr' may be used uninitialized in this function [-Werror=maybe-uninitialized]
      792 |  for (a = rx_grp->arg_macaddr; a != addr; a = a->aua_next)
          |  ^~~
    cc1: all warnings being treated as errors

Testing done: build/install/boot