--- a/certs/Makefile	Fri Dec 03 16:40:42 2010 +0100
+++ b/certs/Makefile	Mon Dec 06 18:48:23 2010 +0000
@@ -11,6 +11,8 @@
 # signing request that you can submit to a CA, or `make yourhost.cert`
 # to generate a self signed certificate.
 
+.PRECIOUS: %.cnf %.key
+
 # To request a cert
 %.csr: %.cnf %.key
 	openssl req -new -key $(lastword $^) -out $@ -utf8 -config $(firstword $^)