Index: /trunk/src/VBox/Devices/Network/lwip-new/src/core/tcp.c
===================================================================
--- /trunk/src/VBox/Devices/Network/lwip-new/src/core/tcp.c	(revision 73511)
+++ /trunk/src/VBox/Devices/Network/lwip-new/src/core/tcp.c	(revision 73512)
@@ -1593,5 +1593,5 @@
   lpcb = (struct tcp_pcb_listen *)pcb;
 
-  lpcb->accept = (tcp_accept_fn)accept_syn;
+  lpcb->accept = (tcp_accept_fn)(uintptr_t)accept_syn;
   lpcb->accept_on_syn = 1;
 }
Index: /trunk/src/VBox/Devices/Network/lwip-new/src/core/tcp_in.c
===================================================================
--- /trunk/src/VBox/Devices/Network/lwip-new/src/core/tcp_in.c	(revision 73511)
+++ /trunk/src/VBox/Devices/Network/lwip-new/src/core/tcp_in.c	(revision 73512)
@@ -584,5 +584,5 @@
        * other callbacks if necessary.
        */
-      accept_syn = (tcp_accept_syn_fn)npcb->accept;
+      accept_syn = (tcp_accept_syn_fn)(uintptr_t)npcb->accept;
       npcb->accept = tcp_accept_null;