diff --git a/doc/doxygen/Makefile.am b/doc/doxygen/Makefile.am
index 76f4cf6b..957aa3de 100644
--- a/doc/doxygen/Makefile.am
+++ b/doc/doxygen/Makefile.am
@@ -2,7 +2,11 @@
 noinst_DATA = xml/index.xml
 dist_noinst_DATA = wayland.doxygen.in
 
-xml/index.xml:
+scanned_src_files = 				\
+	$(top_srcdir)/src/wayland-client.c	\
+	$(top_srcdir)/src/wayland-client.h
+
+xml/index.xml: $(scanned_src_files)
 	doxygen wayland.doxygen
 
 clean-local: