diff --git a/Makefile.am b/Makefile.am
index 7dd8bc2..3880375 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -13,6 +13,8 @@ if ENABLE_DOCUMENTATION
 SUBDIRS += docs
 endif
 
+ACLOCAL_AMFLAGS = -I m4 ${ACLOCAL_FLAGS}
+
 EXTRA_DIST = \
 	MAINTAINERS		\
 	ChangeLog		\
