diff -ur ocamlnet-2.2.9/src/rpc-auth-local/rpclocal.c ocamlnet-2.2.9.new/src/rpc-auth-local/rpclocal.c
--- ocamlnet-2.2.9/src/rpc-auth-local/rpclocal.c	2007-11-01 22:12:33.000000000 +0000
+++ ocamlnet-2.2.9.new/src/rpc-auth-local/rpclocal.c	2008-02-12 21:01:21.000000000 +0000
@@ -3,6 +3,8 @@
  *
  */
 
+#define _GNU_SOURCE /* for SO_PEERCRED / struct ucred */
+
 #include "caml/mlvalues.h"
 #include "caml/alloc.h"
 #include "caml/memory.h"