AX_LIB_READLINE picks up base readline which is too old.  Force it to
use readline from ports.

Index: configure.ac
--- configure.ac.orig
+++ configure.ac
@@ -17,7 +17,8 @@ AC_HEADER_TIOCGWINSZ
 AX_DEBUG_CFLAGS
 AX_WITH_CURSES
 AX_WITH_CURSES_PANEL
-AX_LIB_READLINE
+AC_DEFINE(HAVE_LIBREADLINE, 1, [])
+AC_DEFINE(HAVE_READLINE_READLINE_H, 1, [])
 AX_LIB_POSTGRESQL([],[], AC_MSG_NOTICE([PostgreSQL library not found]))
 
 case "$ax_cv_ncurses" in "no")