misc: Fix compiler warning about incompatible pointers
diff --git a/openbsc/src/bsc/osmo_bsc_main.c b/openbsc/src/bsc/osmo_bsc_main.c
index 3fb9247..62a4e0e 100644
--- a/openbsc/src/bsc/osmo_bsc_main.c
+++ b/openbsc/src/bsc/osmo_bsc_main.c
@@ -51,7 +51,7 @@
 static int daemonize = 0;
 
 extern void bsc_vty_init(void);
-extern int bsc_bootstrap_network(int (*layer4)(struct gsm_network *, int, void *), const char *cfg_file);
+extern int bsc_bootstrap_network(int (*layer4)(struct gsm_network *, struct msgb *), const char *cfg_file);
 
 static void print_usage()
 {