Fix build failure with automake-1.13; fixed upstream in >=2.24.15 and >=3.0
https://bugs.gentoo.org/467520

diff --git a/configure.in b/configure.in
index 27294c8..798a259 100644
--- a/configure.in
+++ b/configure.in
@@ -61,7 +61,7 @@ dnl Initialize automake stuff
 AM_INIT_AUTOMAKE($PACKAGE, $VERSION, no-define)
 
 # Specify a configuration file
-AM_CONFIG_HEADER(config.h)
+AC_CONFIG_HEADERS([config.h])
 
 dnl Initialize libtool
 AC_PROG_LIBTOOL