diff --git a/include/osmocom/vty/vty.h b/include/osmocom/vty/vty.h
index 71b6be0..e5a9d0d 100644
--- a/include/osmocom/vty/vty.h
+++ b/include/osmocom/vty/vty.h
@@ -156,5 +156,5 @@
 int vty_shell_serv (struct vty *);
 void vty_hello (struct vty *);
 
-void *tall_vty_ctx;
+extern void *tall_vty_ctx;
 #endif