Add --fast-dns-retry option.

This gives dnsmasq the ability to originate retries for upstream DNS
queries itself, rather than relying on the downstream client. This is
most useful when doing DNSSEC over unreliable upstream network. It
comes with some cost in memory usage and network bandwidth.

src/util.c

@@ -457,6 +457,15 @@ time_t dnsmasq_time(void)
 #endif
 }
 
+u32 dnsmasq_milliseconds(void)
+{
+  struct timeval tv;
+
+  gettimeofday(&tv, NULL);
+
+  return (tv.tv_sec) * 1000 + (tv.tv_usec / 1000);
+}
+
 int netmask_length(struct in_addr mask)
 {
   int zero_count = 0;