--- a/Makefile.am
+++ b/Makefile.am
@@ -34,6 +34,8 @@ SUBDIRS = include m4 src build obj
 
 DISTCLEANFILES = libtool-disable-static
 
+ACLOCAL_AMFLAGS = -I m4
+
 EXTRA_DIST = \
 	COPYING.FDL \
 	COPYING.GPL \
