Use c99 and update configure script.
Use c99 and update configure script.

deepak899/sctp-refimpl,sctplab/sctp-refimpl,sctplab/sctp-refimpl,xwhuang/sctp-refimpl,deepak899/sctp-refimpl,sctplab/sctp-refimpl,sctplab/sctp-refimpl,deepak899/sctp-refimpl,deepak899/sctp-refimpl,xwhuang/sctp-refimpl,xwhuang/sctp-refimpl,sctplab/sctp-refimpl,sctplab/sctp-refimpl,deepak899/sctp-refimpl,xwhuang/sctp-refimpl,deepak899/sctp-refimpl,xwhuang/sctp-refimpl,xwhuang/sctp-refimpl