export definitions to be used in conjunctions with extraConfigs. With such

method, properties evaluated at the evaluation time are still on the values
which makes this interresting to use in conjunction with extraConfigs.
The extraConfigs values are merged with the other values and then the
properties gets evaluated.

Thus, we can keep properties like mkOverride with this method.

svn path=/nixpkgs/trunk/; revision=17482

pkgs/lib/modules.nix

@@ -216,6 +216,7 @@ rec {
                   definitions =
                     map (m: {
                       source = m.key;
+                      value = m.config;
                     }) (definitionsOf name);
 
                   config = builtins.tryEval