Fix incorrect type.

Upstream bug: https://sourceforge.net/p/libcddb/patches/9/

--- libcddb-1.3.2/lib/cddb_net.c	2009-03-01 03:28:07.000000000 +0000
+++ libcddb-1.3.2/lib/cddb_net.c	2025-07-03 17:58:30.064232649 +0100
@@ -305,7 +305,7 @@
             int rv;
             fd_set wfds;
             struct timeval tv;
-            size_t l;
+            socklen_t l;
 
             /* set up select time out */
             tv.tv_sec = timeout;