nix-ld for NixOS installations #51

While this project was inspired by Nix, in practice it doesn't work very well in NixOS for binaries requiring glibc and the executable would refuse to launch. nix-ld somewhat solves that.

I'm not sure how we should integrate this, but even if it's not a blended-in support, I want the experience to be ~easy to use in NixOS. Loose coupling with the way this project integrates with make or direnv would be fantastic.