Imported from libpng-1.0.5h.tar
diff --git a/scripts/makefile.hpux b/scripts/makefile.hpux
index 780bfe5..1a98fdd 100644
--- a/scripts/makefile.hpux
+++ b/scripts/makefile.hpux
@@ -47,6 +47,10 @@
 clean:
 	rm -f *.o libpng.a pngtest pngout.png
 
+DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO Y2KINFO
+writelock:
+	chmod a-w *.[ch35] $(DOCS) scripts/*
+
 # DO NOT DELETE THIS LINE -- make depend depends on it.
 
 png.o: png.h pngconf.h