diff --git a/gdk-pixbuf/pixops/Makefile.am b/gdk-pixbuf/pixops/Makefile.am
index 354896bbc5..1b7f888502 100644
--- a/gdk-pixbuf/pixops/Makefile.am
+++ b/gdk-pixbuf/pixops/Makefile.am
@@ -1,6 +1,6 @@
 noinst_LTLIBRARIES = libpixops.la
 
-INCLUDES = $(GLIB_CFLAGS)
+INCLUDES = $(GLIB_CFLAGS) $(LIBART_CFLAGS)
 
 bin_PROGRAMS = timescale