Add ability to set the missing DACP port scan interval.

scripts/shairport-sync.conf

@@ -54,7 +54,7 @@ general =
 //	resend_control_first_check_time = 0.10; // Use this optional advanced setting to set the wait time in seconds before deciding a packet is missing.
 //	resend_control_check_interval_time = 0.25; //  Use this optional advanced setting to set the time in seconds between requests for a missing packet.
 //	resend_control_last_check_time = 0.10; // Use this optional advanced setting to set the latest time, in seconds, by which the last check should be done before the estimated time of a missing packet's transfer to the output buffer.
-//
+//	missing_port_dacp_scan_interval_seconds = 2.0; // Use this optional advanced setting to set the time interval between scans for a DACP port number if no port number has been provided by the player for remote control commands
 };
 
 // Advanced parameters for controlling how Shairport Sync stays active and how it runs a session

shairport.c

@@ -806,6 +806,18 @@ int parse_options(int argc, char **argv) {
               dvalue, config.resend_control_last_check_time);
       }
 
+      if (config_lookup_float(config.cfg, "general.missing_port_dacp_scan_interval_seconds",
+                              &dvalue)) {
+        if ((dvalue >= 0.0) && (dvalue <= 300.0))
+          config.missing_port_dacp_scan_interval_seconds = dvalue;
+        else
+          warn("Invalid general missing_port_dacp_scan_interval_seconds setting \"%d\". It should "
+              "be "
+              "between 0.0 and 300.0, "
+              "inclusive. The setting remains at %f seconds.",
+              dvalue, config.missing_port_dacp_scan_interval_seconds);
+      }
+
       /* Get the default latency. Deprecated! */
       if (config_lookup_int(config.cfg, "latencies.default", &value))
         config.userSuppliedLatency = value;