Declare a complete prototype for the function pointer *ext_free and the function m_devget.
Declare a complete prototype for the function pointer *ext_free and the
function m_devget.

Uniformize idempotency ifdef.

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