stricter type usage for time variables to avoid picky compiler warnings

lib/tftp.c

@@ -186,12 +186,12 @@ void tftp_set_timeouts(tftp_state_data_t *state)
 {
 
   struct SessionHandle *data = state->conn->data;
-  unsigned long         maxtime, timeout;
+  time_t maxtime, timeout;
 
   time(&state->start_time);
   if(state->state == TFTP_STATE_START) {
     /* Compute drop-dead time */
-    maxtime = data->set.connecttimeout?data->set.connecttimeout:30;
+    maxtime = (time_t)(data->set.connecttimeout?data->set.connecttimeout:30);
     state->max_time = state->start_time+maxtime;
 
     /* Set per-block timeout to total */