does not install xml files twice
--- lib/Makefile.in.orig
+++ lib/Makefile.in
@@ -1054,7 +1054,6 @@ info-am: $(INFO_DEPS)
 install-data-am: install-includeHEADERS install-info-am \
 	install-pkgdataDATA
 	@$(NORMAL_INSTALL)
-	$(MAKE) $(AM_MAKEFLAGS) install-data-hook
 install-dvi: install-dvi-recursive
 
 install-dvi-am: $(DVIS)