chore: add basic flake.nix to build instrument-hooks

Author: GuillaumeLagrange

flake.lock

@@ -0,0 +1,26 @@
+{
+  description = "Development environment for codspeed-rust";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs =
+    {
+      self,
+      nixpkgs,
+      flake-utils,
+    }:
+    flake-utils.lib.eachDefaultSystem (
+      system:
+      let
+        pkgs = nixpkgs.legacyPackages.${system};
+      in
+      {
+        devShells.default = (pkgs.mkShell.override { stdenv = pkgs.clangStdenv; }) {
+          LIBCLANG_PATH = "${pkgs.libclang.lib}/lib";
+        };
+      }
+    );
+}