diff --git a/src/openvpn/route.c b/src/openvpn/route.c
index 156a99eb..05a0c8f4 100644
--- a/src/openvpn/route.c
+++ b/src/openvpn/route.c
@@ -2221,6 +2221,7 @@ delete_route_ipv6(const struct route_ipv6 *r6, const struct tuntap *tt, const st
         device = r6->iface;
         gateway_needed = true;
     }
+    (void)device; /* unused on some platforms */
 
     /* if we used a gateway on "add route", we also need to specify it on
      * delete, otherwise some OSes will refuse to delete the route