* Fix eval-release.nix by testing whether all attributes of a

derivation evaluate inside the tryEval.  This catches cases such as
  aufs2-util, which fails due to an assertion in its dependency aufs2.
* Explicitly blacklist "xbursttools" because it gives some
  evaluation error in cross-OpenSSL.  No idea why, probably due to
  some pass-through attribute.

svn path=/nixpkgs/trunk/; revision=23247

pkgs/lib/customisation.nix

@@ -54,7 +54,7 @@ rec {
         makeOverridable f (origArgs // (if builtins.isFunction newArgs then newArgs origArgs else newArgs));
       deepOverride = newArgs:
         makeOverridable f (lib.overrideExisting (lib.mapAttrs (deepOverrider newArgs) origArgs) newArgs);
-      origArgs = origArgs;
+      #origArgs = origArgs;
     };
 
   deepOverrider = newArgs: name: x: if builtins.isAttrs x then (

pkgs/lib/trivial.nix

@@ -18,4 +18,8 @@ rec {
   # Flip the order of the arguments of a binary function.
   flip = f: a: b: f b a;
 
+  # `seq x y' evaluates x, then returns y.  That is, it forces strict
+  # evaluation of its first argument.
+  seq = x: y: if x == null then y else y;
+  
 }