librdf_redland: Fix dependency on libraptor2

This broke soprano/nepomuk.

http://hydra.nixos.org/build/32556702

pkgs/development/libraries/librdf/redland.nix

@@ -30,6 +30,9 @@ stdenv.mkDerivation rec {
     [ "--with-threads" ]
     ++ stdenv.lib.optional withBdb "--with-bdb=${db}";
 
+  # Fix broken DT_NEEDED in lib/redland/librdf_storage_sqlite.so.
+  NIX_CFLAGS_LINK = "-lraptor2";
+
   meta = {
     homepage = http://librdf.org/;
   };