+# generate program documentation
+.PHONY: autodoc
+autodoc: autodoc_xref $(AUTODOCDIR) $(GLOBALXREFFILE) autodoc_html $(INDEXFILE)
+
+$(GLOBALXREFFILE): $(addsuffix /$(LOCALXREFSFILE), $(subdirs)) .xrefs
+# cat $^ > $@
+ $(RM) $@
+ find $(PWD) -name "*.xref" -print > $@
+
+$(INDEXFILE): $(GLOBALXREFFILE)
+ $(AUTODOC) $(GLOBALXREFFILE) $@ INDEX HTML
+
+