Fix garbage value in socketpair util function, stdint? * Fixed an issue with evutil_ersatz_socketpair_, listen_addr could all be compared against with agarbage values. So just memset it before using it anywhere. * Nick might punch me in the face, but if we have stdint.h; (as in EVENT__HAVE_STDINT_H is defined), might as well use those instead of the manual [U]INT[X}_MAX/MIN muck in there now.