diff --git a/src/ppp-manager/Makefile.am b/src/ppp-manager/Makefile.am
index 06d8013955..a504a6a9fd 100644
--- a/src/ppp-manager/Makefile.am
+++ b/src/ppp-manager/Makefile.am
@@ -4,6 +4,7 @@ AM_CPPFLAGS = \
 	-I${top_builddir}/include \
 	-I${top_srcdir}/include \
 	-I${top_srcdir}/libnm-util \
+	-I${top_builddir}/libnm-util \
 	-DG_LOG_DOMAIN=\""nm-pppd-plugin"\" \
 	-DNM_VERSION_MAX_ALLOWED=NM_VERSION_NEXT_STABLE \
 	$(DBUS_CFLAGS) \