Nix: use specific version of Nodejs and set LD_LIBRARY_PATH

shell.nix

{ pkgs ? import <nixpkgs> { } }:
with pkgs;
mkShell {
  buildInputs = [
    fish
    git
    nodejs-12_x
    (yarn.override { nodejs = nodejs-12_x; })
    gnumake
    python3
    gccStdenv
    eudev
    libusb1
    libusb1.dev
    pkg-config
    which
  ];

  LD_LIBRARY_PATH="${libusb1}/lib";
}