One solution to https://github.com/raspberrypi/firmware/issues/112

It is probably a bug that client_tls was not set during eglGetDisplay.

This patch imitates the behavior that happens when you load libvcos.so before using thread-local storage in your program, like how node.js is doing. So it might not fix the actual bug. Works for GLESv2 at least. Can't check with node-openvg because it requires eglGetDisplay to be called before loading.

I don't know enough about the wrapping to do better yet.