diff --git a/gnulib/lib/Makefile.am b/gnulib/lib/Makefile.am
index 601f74073c..5669551afb 100644
--- a/gnulib/lib/Makefile.am
+++ b/gnulib/lib/Makefile.am
@@ -26,3 +26,5 @@ SUFFIXES =
 noinst_LTLIBRARIES =
 
 include gnulib.mk
+
+AM_CPPFLAGS = -I$(top_srcdir)