Improve compilation if INET or INET6 is not defined.
Improve compilation if INET or INET6 is not defined.

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