[gdl] Fix build with automake 1.13

[Sebastien Granjoux <sgranjoux src gnome org>]

commit b2f4d39827f12550eb548b402176198c65711bc3
Author: Marcin Banasiak <marcin banasiak gmail com>
Date:   Sun Mar 24 20:39:29 2013 +0100

    Fix build with automake 1.13
    
    In automake 1.13 AM_CONFIG_HEADER has been removed in favour of
    AC_CONFIG_HEADERS.

 configure.in | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/configure.in b/configure.in
index 2f1a3b2..dec8c13 100644
--- a/configure.in
+++ b/configure.in
@@ -8,7 +8,7 @@ dnl ==========================================================================
 AC_PREREQ(2.65)
 AC_INIT(gdl)
 AC_CONFIG_MACRO_DIR([m4])
-AM_CONFIG_HEADER(config.h)
+AC_CONFIG_HEADERS([config.h])
 
 GDL_MAJOR_VERSION=3
 GDL_MINOR_VERSION=9