OpenJDK support

[Pjotr Prins]

To support the JVM we'll need to add the openjdk.

Having a look at it I think it is doable. Only problem is that the
java compiler needs to be bootstrapped with itself. 

In Nix they create a binary blob to bootstrap:

    let
      # !!! These should be on nixos.org
      src = if glibc.system == "x86_64-linux" then
        fetchurl {
          url = 
http://tarballs.nixos.org/openjdk-bootstrap-x86_64-linux-2012-08-2
    4.tar.xz;
          sha256 = "0gla9dxrfq2w1hvgsnn8jg8a60k27im6z43a6iidi0qmwa0wah32";
        }
      else if glibc.system == "i686-linux" then
        fetchurl {
          url = 
http://tarballs.nixos.org/openjdk-bootstrap-i686-linux-2012-08-24.
    tar.xz;
          sha256 = "184wq212bycwbbq4ix8cc6jwjxkrqw9b01zb86q95kqpa8zy5206";
        }
      else throw "No bootstrap for system";
    in

How do we go about this one?

Pj.