fix segfault problem in libreadline, cfr. http://ftp.gnu.org/gnu/readline/readline-6.3-patches/readline63-002
--- readline-6.3.orig/readline.c	2013-10-28 19:58:06.000000000 +0100
+++ readline-6.3/readline.c	2016-05-20 14:09:43.322571000 +0200
@@ -744,7 +744,8 @@
     r = _rl_subseq_result (r, cxt->oldmap, cxt->okey, (cxt->flags & KSEQ_SUBSEQ));
 
   RL_CHECK_SIGNALS ();
-  if (r == 0)			/* success! */
+  /* We only treat values < 0 specially to simulate recursion. */
+  if (r >= 0 || (r == -1 && (cxt->flags & KSEQ_SUBSEQ) == 0))   /* success! or failure! */
     {
       _rl_keyseq_chain_dispose ();
       RL_UNSETSTATE (RL_STATE_MULTIKEY);
