Update the autoconf stuff
diff --git a/configure.in b/configure.in
index b3691d5..3176b1d 100644
--- a/configure.in
+++ b/configure.in
@@ -3,20 +3,24 @@
 dnl
 dnl Process this file with autoconf to produce a configure script.
 dnl
+
+AC_PREREQ(2.50)
 AC_INIT()
 
-AM_MAINTAINER_MODE
-
 AM_INIT_AUTOMAKE(bluez-libs, 2.6)
 
+AM_MAINTAINER_MODE
+
 AC_PREFIX_DEFAULT(/usr)
 
 CFLAGS="-Wall -g -O2"
 
+AC_LANG_C
+
 AC_PROG_CC
 AC_PROG_INSTALL
 
-dnl AC_LIBTOOL_TAGS([])
+m4_ifdef([AC_LIBTOOL_TAGS], [AC_LIBTOOL_TAGS([])])
 
 AC_PROG_LIBTOOL