Address some signed/unsigned issues.
Address some signed/unsigned issues.

sctplab/usrsctp,weinrank/usrsctp,CoolmanCZ/usrsctp,weinrank/usrsctp,JlnWntr/usrsctp,sctplab/usrsctp,CoolmanCZ/usrsctp,JlnWntr/usrsctp,CoolmanCZ/usrsctp,faithfracture/usrsctp,weinrank/usrsctp,JlnWntr/usrsctp,faithfracture/usrsctp,faithfracture/usrsctp,CoolmanCZ/usrsctp,sctplab/usrsctp