* Added an experimental feature suggested by Andres: ellipses ("...")

in attribute set pattern matches.  This allows defining a function
  that takes *at least* the listed attributes, while ignoring
  additional attributes.  For instance,

    {stdenv, fetchurl, fuse, ...}:
    
    stdenv.mkDerivation {
      ...
    };
    
  defines a function that requires an attribute set that contains the 
  specified attributes but ignores others.  The main advantage is that
  we can then write in all-packages.nix

    aefs = import ../bla/aefs pkgs;

  instead of

    aefs = import ../bla/aefs {
      inherit stdenv fetchurl fuse;
    };

  This saves a lot of typing (not to mention not having to update
  all-packages.nix with purely mechanical changes).  It saves as much
  typing as the "args: with args;" style, but has the advantage that
  the function arguments are properly declared (not implicit in what
  the body of the "with" uses).

tests/lang/eval-okay-xml.exp.xml

@@ -22,6 +22,16 @@
     <attr name="c">
       <string value="foobar" />
     </attr>
+    <attr name="ellipsis">
+      <function>
+        <attrspat>
+          <attr name="x" />
+          <attr name="y" />
+          <attr name="z" />
+          <ellipsis />
+        </attrspat>
+      </function>
+    </attr>
     <attr name="f">
       <function>
         <attrspat>