upstream: https://github.com/processone/ejabberd/pull/628
Author: Johan Oudinet <johan.oudinet@gmail.com>

From 0e7d2b73be335353e9938668a699b3dbb7011c56 Mon Sep 17 00:00:00 2001
From: Johan Oudinet <johan.oudinet@gmail.com>
Date: Tue, 30 Jun 2015 10:53:45 +0200
Subject: [PATCH] configure.ac: add AC_CONFIG_MACRO_DIR

Otherwise, autoconf fails to find extra macros defined in the m4
directory.
---
 configure.ac | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/configure.ac b/configure.ac
index a3e2638..0a60de0 100644
--- a/configure.ac
+++ b/configure.ac
@@ -6,6 +6,8 @@ AC_INIT(ejabberd, m4_esyscmd([echo `git describe --tags 2>/dev/null || echo 0.0`
 REQUIRE_ERLANG_MIN="5.9.1 (Erlang/OTP R15B01)"
 REQUIRE_ERLANG_MAX="9.0.0 (No Max)"
 
+AC_CONFIG_MACRO_DIR([m4])
+
 # Checks for programs.
 AC_PROG_MAKE_SET
 AC_PROG_INSTALL
-- 
2.1.4