No warnings here any more.
diff --git a/isisd/isis_dr.c b/isisd/isis_dr.c
index c6c9e58..0ee173e 100644
--- a/isisd/isis_dr.c
+++ b/isisd/isis_dr.c
@@ -50,7 +50,7 @@
 extern struct isis *isis;
 extern struct thread_master *master;
 
-char *
+const char *
 isis_disflag2string (int disflag)
 {