fix mingw32 sse2 crash and assertion failure (winxp)

configure.ac

@@ -531,7 +531,7 @@ AS_CASE(["$ARG_ENABLE_SSE2"],
   ["yes"|"on"], [
       AC_MSG_RESULT([yes])
       AC_DEFINE([USE_SSE2],[1],[Enable SSE2])
-      CXXFLAGS="$CXXFLAGS -DUSE_SSE2 -msse2 "
+      CXXFLAGS="$CXXFLAGS -DUSE_SSE2 -msse2 -mstackrealign "
     ],
   ["no"|"off"], [
       AC_MSG_RESULT([no])

libtorrent/src/utp_stream.cpp

@@ -2161,7 +2161,7 @@ void utp_socket_impl::ack_packet(packet* p, ptime const& receive_time
 		rtt = 100000;
 
 		// the clock for this plaform is not monotonic!
-		TORRENT_ASSERT(false);
+		//TORRENT_ASSERT(false);
 	}
 
 	UTP_LOGV("%8p: acked packet %d (%d bytes) (rtt:%u)\n"