do not leak addrinfo in configure test
diff --git a/configure.ac b/configure.ac
index 2ccb4e2..fb2ae67 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3700,6 +3700,8 @@
         break;
       }
     }
+    freeaddrinfo(aitop);
+    aitop = NULL;
   }
 
   if (!(inet4 == 0 || inet4 == 2))