Remove dependency on flake-utils

This reverts commit b5abb09507.

flake-template.nix

@@ -0,0 +1,23 @@
+{
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable-small";
+
+  outputs =
+    { self, nixpkgs, ... }:
+    let
+      system = "x86_64-linux";
+    in
+    {
+      devShells."${system}".default =
+        let
+          pkgs = import nixpkgs {
+            inherit system;
+          };
+        in
+        pkgs.mkShell {
+          packages = with pkgs; [
+          ];
+
+          shellHook = "";
+        };
+    };
+}

nix-ld.nix

@@ -0,0 +1,8 @@
+{ pkgs ? import <nixpkgs> { } }:
+
+with pkgs;
+
+mkShell {
+  NIX_LD_LIBRARY_PATH = lib.makeLibraryPath [ stdenv.cc.cc openssl ];
+  NIX_LD = lib.fileContents "${stdenv.cc}/nix-support/dynamic-linker";
+}

shell.nix

@@ -0,0 +1,9 @@
+{ pkgs ? import <nixpkgs> {} }:
+
+with pkgs;
+
+mkShell {
+  buildInputs = [
+
+  ];
+}