[automerger] Add extra (size_t) cast to avoid compiler warning. am: 1387a89b14 am: bc2ee79a6e am: 53787550a7 am: 95129dbdb6 am: 10d8009592

Change-Id: I86a2e1dc9105493c9d4c00609195544c2b040ad5
diff --git a/src/rfc1035.c b/src/rfc1035.c
index a12c3b0..d13f5bf 100755
--- a/src/rfc1035.c
+++ b/src/rfc1035.c
@@ -1142,7 +1142,7 @@
   struct mx_srv_record *rec;
   // Make sure we do not underflow here too.
-  if (qlen > (limit - ((char *)header))) return 0;
+  if (qlen > (size_t)(limit - ((char *)header))) return 0;
   /* If there is an RFC2671 pseudoheader then it will be overwritten by
      partial replies, so we have to do a dry run to see if we can answer