diff --git a/Makefile.am b/Makefile.am
index 30fe5f9..1b8a973 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,6 +1,6 @@
 SUBDIRS = src po help
 
-ACLOCAL_AMFLAGS = -I m4
+ACLOCAL_AMFLAGS = -I m4 ${ACLOCAL_FLAG}
 
 NULL =