Emit warning if ifconf_to_smartlist() isn't included.
Fixing header file so that SIOCGIFCONF symbol is included before address.h:32.
Revert "Emit warning if ifconf_to_smartlist() isn't included."

This reverts commit c9e234e19047f19dba97791b16efefe1beefd1a1.
Silencing compiler warning regarding uninitialized/unused variables.