Merge pull request #1328 from DL6ER/fix/crash_all_optional

 Prevent crash on no bound ports

src/civetweb.c

@@ -20563,7 +20563,7 @@ master_thread_run(struct mg_context *ctx)
 	unsigned int i;
 	unsigned int workerthreadcount;
 
-	if (!ctx) {
+	if (!ctx || !ctx->listening_socket_fds) {
 		return;
 	}