${srcdir}/oldXMenu/Makefile.in, not itself.
@${srcdir}/move-if-change src/Makefile.tmp src/Makefile
chmod -w src/Makefile
-oldXMenu/Makefile: ${srcdir}/oldXMenu/Makefile Makefile
+oldXMenu/Makefile: ${srcdir}/oldXMenu/Makefile.in Makefile
rm -f oldXMenu/Makefile.tmp
@echo "Producing \`oldXMenu/Makefile' from \`${srcdir}/oldXMenu/Makefile'."
@(echo "# This file is generated from \`${srcdir}/oldXMenu/Makefile'." ; \