Improve compilation when not INET and INET6 are defined.
Improve compilation when not INET and INET6 are defined.

CoolmanCZ/usrsctp,weinrank/usrsctp,sctplab/usrsctp,liamstask/usrsctp,faithfracture/usrsctp,CoolmanCZ/usrsctp,JlnWntr/usrsctp,faithfracture/usrsctp,faithfracture/usrsctp,saghul/usrsctp,CoolmanCZ/usrsctp,saghul/usrsctp,sctplab/usrsctp,ossy-szeged/usrsctp,CoolmanCZ/usrsctp,sctplab/usrsctp,bebo/usrsctp,ossy-szeged/usrsctp,sukinull/usrsctp,bebo/usrsctp,liamstask/usrsctp,JlnWntr/usrsctp,weinrank/usrsctp,sukinull/usrsctp,weinrank/usrsctp,JlnWntr/usrsctp