dns_enqueue(): minor readability improvement: add local variable "age" to store result of subtraction
diff --git a/src/core/dns.c b/src/core/dns.c
index 2aa1dd9..65355be 100644
--- a/src/core/dns.c
+++ b/src/core/dns.c
@@ -1244,8 +1244,9 @@
     }
     /* check if this is the oldest completed entry */
     if (entry->state == DNS_STATE_DONE) {
-      if ((u8_t)(dns_seqno - entry->seqno) > lseq) {
-        lseq = dns_seqno - entry->seqno;
+      u8_t age = dns_seqno - entry->seqno;
+      if (age > lseq) {
+        lseq = age;
         lseqi = i;
       }
     }