api_msg.c, dns.h, dns.c: Implement DNS_DOES_NAME_CHECK option (check if name received match the name query), implement DNS_USES_STATIC_BUF (the place where copy dns payload to parse the response), return an error if there is no place for a new query, and fix some minor problems.

src/api/api_msg.c

@@ -1032,6 +1032,9 @@ do_gethostbyname(void *arg)
     if (res == DNS_COMPLETE) {
       /* name was already in octet notation or cached */
       *msg->err = ERR_OK;
+    } else if (res == DNS_ERR_MEM) {
+      /* memory allocation error */
+      *msg->err = ERR_MEM;
     } else {
       /* some error occurred */
       *msg->err = ERR_ARG;