diff --git a/demo/Makefile.am b/demo/Makefile.am
index 3684a03..3a1d059 100644
--- a/demo/Makefile.am
+++ b/demo/Makefile.am
@@ -1,6 +1,7 @@
 generated_sources = searpc-signature.h searpc-marshal.h
 
 AM_CFLAGS = @GLIB_CFLAGS@ \
+	@JANSSON_CFLAGS@ \
 	-I${top_srcdir}/lib
 
 # we need to generate the first