diff --git a/Makefile.am b/Makefile.am
index 1835005..41ff37c 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,3 +1,5 @@
+ACLOCAL_AMFLAGS = -I m4
+
 SUBDIRS = libnotify docs tools tests
 
 pcdata_DATA = libnotify.pc