libwebp: Update to new upstream version 0.4.0.

Now the version should be recent enough to be built against Chromium,
see: https://code.google.com/p/webp/issues/detail?id=122#c6

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

pkgs/development/libraries/libwebp/default.nix

@@ -1,11 +1,11 @@
 {stdenv, fetchurl, libpng, libjpeg}:
 
 stdenv.mkDerivation rec {
-  name = "libwebp-0.1.3";
-  
+  name = "libwebp-0.4.0";
+
   src = fetchurl {
     url = "http://webp.googlecode.com/files/${name}.tar.gz";
-    sha256 = "1fkssvg99s9ypswh4ywkirgcy1wmy3b6388f3cqj4a4vwdb89ca0";
+    sha256 = "0sadjkx8m6sf064r5gngjvz4b5246q3j27dlaml5b1k3x5vkb49i";
   };
 
   buildInputs = [ libpng libjpeg ];