openjdk: Don't statically link C++ runtime.

This fixes a build error (https://github.com/NixOS/nixpkgs/issues/707).  openjdk compiles but I haven't tested to see if it works.
Thanks to http://mail.openjdk.java.net/pipermail/build-dev/2012-January/005349.html .

I am providing this patch to you under an open source license. Because I have done this work with my own personal resources, the license you receive to my code is from me and not from my employer (Facebook).