fix windows build a different way

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@13537 d0543943-73ff-0310-b7d9-9358b9ac24b2

libs/libnatpmp/natpmp.c

@@ -183,7 +183,7 @@ int readnatpmpresponse(natpmp_t * p, natpmpresp_t * response)
 	int n;
 	if(!p)
 		return NATPMP_ERR_INVALIDARGS;
-	n = recvfrom(p->s, buf, sizeof(buf), 0,
+	n = recvfrom(p->s, (char *)buf, sizeof(buf), 0,
 	             (struct sockaddr *)&addr, &addrlen);
 	if(n<0)
 		switch(errno) {