From b69143b5085c58e51ab8077ee5cbe6fafe73e041 Mon Sep 17 00:00:00 2001
From: Dan Williams <dcbw@redhat.com>
Date: Tue, 14 Oct 2014 14:30:44 -0500
Subject: [PATCH] build: ensure rl_echo_signal_char() exists in the readline
 library

---
 m4/ax_lib_readline.m4 | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/m4/ax_lib_readline.m4 b/m4/ax_lib_readline.m4
index 72764fba5..8a05574f2 100644
--- a/m4/ax_lib_readline.m4
+++ b/m4/ax_lib_readline.m4
@@ -92,6 +92,8 @@ AC_DEFUN([AX_LIB_READLINE], [
 
   LIBS="$LIBS $ax_cv_lib_readline"
   AC_CHECK_HEADERS(readline.h readline/readline.h)
+
+  # Check history
   AC_CACHE_CHECK([whether readline supports history],
                  ax_cv_lib_readline_history, [
     ax_cv_lib_readline_history="no"
@@ -101,6 +103,17 @@ AC_DEFUN([AX_LIB_READLINE], [
     AC_MSG_ERROR(readline history support is required)
   fi
   AC_CHECK_HEADERS(history.h readline/history.h)
+
+  # check rl_echo_signal_char()
+  AC_CACHE_CHECK([whether readline supports rl_echo_signal_char()],
+                 ax_cv_lib_readline_echo_signal_char, [
+    ax_cv_lib_readline_echo_signal_char="no"
+    AC_TRY_LINK_FUNC(rl_echo_signal_char, ax_cv_lib_readline_echo_signal_char="yes")
+  ])
+  if test "$ax_cv_lib_readline_echo_signal_char" != "yes"; then
+    AC_MSG_ERROR(rl_echo_signal_char() is required (install readline6?))
+  fi
+
   READLINE_LIBS="$ax_cv_lib_readline"
   AC_SUBST(READLINE_LIBS)
 ])dnl