diff --git a/Makefile.am b/Makefile.am
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,6 +1,6 @@
 ACLOCAL_AMFLAGS = -I m4
 
-AM_CPPFLAGS = -I$(top_srcdir)
+AM_CPPFLAGS = -I$(top_srcdir) -I$(top_builddir)
 LDADD = $(top_builddir)/lemon/libemon.la
 
 EXTRA_DIST = \