OSX `touch` has no "--reference" long-option, only "-r"

doc/makefile

@@ -26,14 +26,14 @@ doxy: doxygen
 crypt.pdf: crypt.tex
 	rm -f crypt.pdf $(LEFTOVERS)
 	cp crypt.tex crypt.bak
-	touch --reference=crypt.tex crypt.bak
+	touch -r crypt.tex crypt.bak
 	(printf "%s" "\def\fixedpdfdate{"; date +'D:%Y%m%d%H%M%S%:z' -d @$$(stat --format=%Y crypt.tex) | sed "s/:\([0-9][0-9]\)$$/'\1'}/g") > crypt-deterministic.tex
 	printf "%s\n" "\pdfinfo{" >> crypt-deterministic.tex
 	printf "%s\n" "  /CreationDate (\fixedpdfdate)" >> crypt-deterministic.tex
 	printf "%s\n}\n" "  /ModDate (\fixedpdfdate)" >> crypt-deterministic.tex
 	cat crypt.tex >> crypt-deterministic.tex
 	mv crypt-deterministic.tex crypt.tex
-	touch --reference=crypt.bak crypt.tex
+	touch -r crypt.bak crypt.tex
 	echo "hello" > crypt.ind
 	latex crypt $(silent_stdout)
 	latex crypt $(silent_stdout)