* Added syntactic sugar to the construction of attribute sets to

`inherit' variables from the surrounding lexical scope.

  E.g.,

    {stdenv, libfoo}: derivation {
      builder = ./bla;
      inherit stdenv libfoo;
      xyzzy = 1;
    }

  is equivalent to

    {stdenv, libfoo}: derivation {
      builder = ./bla;
      stdenv = stdenv;
      libfoo = libfoo;
      xyzzy = 1;
    }

  Note that for mutually recursive attribute set definitions (`rec
  {...}'), this also works, that is, `rec {inherit x;}' is equivalent
  to `let {fresh = x; body = rec {x = fresh;};}', *not*
  `rec {x = x}'.

src/libexpr/primops.cc

@@ -96,7 +96,7 @@ static string processBinding(EvalState & state, Expr e, StoreExpr & ne)
         return st.str();
     }
 
-    if (atMatch(m, e) >> "Attrs" >> es) {
+    if (atMatch(m, e) >> "Attrs") {
         Expr a = queryAttr(e, "type");
         if (a && evalString(state, a) == "derivation") {
             a = queryAttr(e, "drvPath");