--- tinc	2012-12-13 11:41:47.000000000 +0100
+++ /etc/network/if-pre-up.d/tinc	2012-11-19 18:01:48.000000000 +0100
@@ -6,7 +6,7 @@
 
 # Read options from /etc/default
 
-. /etc/default/tinc
+[ -r /etc/default/tinc ] && . /etc/default/tinc
 
 # Read options from /etc/network/interfaces