diff --git a/make/doxygen.mk b/make/doxygen.mk
index e66ef820..4561950c 100644
--- a/make/doxygen.mk
+++ b/make/doxygen.mk
@@ -78,7 +78,8 @@ install.doxygen:
 		$(wildcard $(DX_OUTPUT_DIR)/*.png) \
 		$(wildcard $(DX_OUTPUT_DIR)/*.css) \
 		$(DX_INSTALL_DIR)
-%: %.tmpl
+
+$(DX_DOXYGEN_CONF): $(firstword $(wildcard $(DX_DOXYGEN_CONF).tmpl $(DX_FALLBACK_CONF_TMPL)))
 	$(SED) " \
 		s/__VERSION__/$(DIST_VERSION)/g; \
 		s/__PROJECT__/$(PROJECT)/g; \