Building nodejs package with native dependencies

override.nix

{pkgs ? import /root/nixpkgs {
    inherit system;
}, system ? builtins.currentSystem}:

let
  nodePackages = import ./default.nix {
    inherit pkgs system;
  };
in
nodePackages // {
  "sharp-0.21.3" = nodePackages."sharp-0.21.3".override {
    buildInputs = [ pkgs.pkgconfig pkgs.node-gyp pkgs.vips ];
    # https://github.com/lovell/sharp/blob/master/lib/libvips.js#L70
    PKG_CONFIG_PATH = "${pkgs.vips}/lib/pkgconfig";
  };
}