Slightly restructure the #ifdef INET6 sections to make the code more readable.
Slightly restructure the #ifdef INET6 sections to make the code
more readable.

Remove the six "register" attributes from variables tcp_output(), the
compiler surely knows well how to allocate them.

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