diff --git a/src/hb-ucdn/Makefile.am b/src/hb-ucdn/Makefile.am
index 40d6055c1..0670b5c33 100644
--- a/src/hb-ucdn/Makefile.am
+++ b/src/hb-ucdn/Makefile.am
@@ -7,7 +7,7 @@ libhb_ucdn_la_SOURCES = \
 	ucdn.h \
 	ucdn.c \
 	unicodedata_db.h
-libhb_ucdn_CPPFLAGS = \
+libhb_ucdn_la_CPPFLAGS = \
 	-I$(top_srcdir) \
 	-I$(top_srcdir)/src \
 	-I$(top_builddir)/src