64-bit time_t

Index: src/Ntop.cpp
--- src/Ntop.cpp.orig
+++ src/Ntop.cpp
@@ -3044,7 +3044,7 @@ void Ntop::resetStats() {
   char buf[32];
   last_stats_reset = time(NULL);
 
-  snprintf(buf, sizeof(buf), "%ld", last_stats_reset);
+  snprintf(buf, sizeof(buf), "%lld", (long long)last_stats_reset);
 
   /* Saving this is essential to reset inactive hosts across ntopng restarts */
   getRedis()->set(LAST_RESET_TIME, buf);