diff --git a/configure.ac b/configure.ac
index 7f882092..7b9cc0e3 100644
--- a/configure.ac
+++ b/configure.ac
@@ -41,7 +41,7 @@ AC_PREREQ(2.59)
 #
 AC_INIT([ethercat],[1.5.2],[fp@igh-essen.com])
 AC_CONFIG_AUX_DIR([autoconf])
-AM_INIT_AUTOMAKE([-Wall -Werror dist-bzip2])
+AM_INIT_AUTOMAKE([-Wall -Werror dist-bzip2 subdir-objects])
 AC_PREFIX_DEFAULT([/opt/etherlab])
 AC_CONFIG_HEADERS([config.h])
 AC_CONFIG_SRCDIR([config.h.in])