References: https://www.illumos.org/issues/3021 https://www.illumos.org/issues/3022 https://www.illumos.org/issues/3023 https://www.illumos.org/issues/3024 https://www.illumos.org/issues/3025 https://www.illumos.org/issues/3026 Obtained from: ssh://anonhg@hg.illumos.org/illumos-gate
illumos-gate revision 13742:b6bbdd77139c Obtained from: ssh://anonhg@hg.illumos.org/illumos-gate
and so they are needed for constructing pid and usdt probes.