Add opt_inet.h which has been needed since r184714, r184715 introducing checks for #ifdef INET.
Add opt_inet.h which has been needed since r184714, r184715 introducing
checks for #ifdef INET.

Submitted by:	kmacy (r184876, I splitted lines)
MFC after:	54 days

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase