Nix - introduce direnv with nix for shared devel environment

.envrc

@@ -0,0 +1,5 @@
+# shellcheck shell=bash
+if ! has nix_direnv_version || ! nix_direnv_version 3.0.6; then
+  source_url "https://raw.githubusercontent.com/nix-community/nix-direnv/3.0.6/direnvrc" "sha256-RYcUJaRMf8oF5LznDrlCXbkOQrywm0HDv1VjYGaJGdM="
+fi
+use flake

.gitignore

@@ -9,3 +9,6 @@ build/
 
 # Clangd cache files
 .clang/
+
+# Direnv files
+.direnv

flake.nix

@@ -0,0 +1,38 @@
+{
+  description = "A basic flake with a shell";
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+  inputs.systems.url = "github:nix-systems/default";
+  inputs.netmonpkgs.url = "github:jaroslavpesek/netmonpkgs";
+  inputs.flake-utils = {
+    url = "github:numtide/flake-utils";
+    inputs.systems.follows = "systems";
+  };
+
+  outputs =
+    { nixpkgs, flake-utils, netmonpkgs, ... }:
+    flake-utils.lib.eachDefaultSystem (
+      system:
+      let
+        pkgs = nixpkgs.legacyPackages.${system};
+      in
+      {
+        devShells.default = pkgs.mkShell {
+          packages = [
+            pkgs.bashInteractive
+            pkgs.nixd
+            pkgs.nixpkgs-fmt
+            pkgs.cmake
+            pkgs.gcc
+            pkgs.pkg-config
+            pkgs.ncurses
+            pkgs.fuse3
+            pkgs.rpm
+            pkgs.clang
+            netmonpkgs.packages.x86_64-linux.nemea-modules-meta
+            netmonpkgs.packages.x86_64-linux.nemea-framework
+            netmonpkgs.packages.x86_64-linux.telemetry
+          ];
+        };
+      }
+    );
+}