diff --git a/zebra/ioctl_null.c b/zebra/ioctl_null.c
index 6d8e13a..5d046d3 100644
--- a/zebra/ioctl_null.c
+++ b/zebra/ioctl_null.c
@@ -19,16 +19,29 @@
 }
 
 int if_prefix_add_ipv6 (struct interface *a, struct connected *b) { return 0; }
+#ifdef HAVE_SYS_WEAK_ALIAS_PRAGMA
 #pragma weak if_prefix_delete_ipv6 = if_prefix_add_ipv6
+#else
+int if_prefix_delete_ipv6 (struct interface *a, struct connected *b) { return 0; }
+#endif
 
 int if_ioctl (u_long a, caddr_t b) { return 0; }
 
 int if_set_flags (struct interface *a, uint64_t b) { return 0; }
+#ifdef HAVE_SYS_WEAK_ALIAS_PRAGMA
 #pragma weak if_unset_flags = if_set_flags
+#else
+int if_unset_flags (struct interface *a, uint64_t b) { return 0; }
+#endif
 
 void if_get_flags (struct interface *a) { return; }
+#ifdef HAVE_SYS_WEAK_ALIAS_PRAGMA
 #pragma weak if_get_metric = if_get_flags
 #pragma weak if_get_mtu = if_get_flags
+#else
+/* void if_get_metric (struct interface *a) { return; } */
+/* void if_get_mtu (struct interface *a) { return; } */
+#endif
 
 #ifdef SOLARIS_IPV6
 #pragma weak if_ioctl_ipv6 = if_ioctl