add direnv config and shell.nix

.envrc

@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+# the shebang is ignored, but nice for editors
+
+if type -P lorri &>/dev/null; then
+  eval "$(lorri direnv)"
+else
+  echo 'while direnv evaluated .envrc, could not find the command "lorri" [https://github.com/nix-community/lorri]'
+  use nix
+fi

shell.nix

@@ -0,0 +1,34 @@
+{ pkgs ? import <nixpkgs> {} }:
+
+let llvmPackage = pkgs.llvmPackages_17;
+    stdenv = llvmPackage.libcxxStdenv;
+    libcxx = llvmPackage.libraries.libcxx;
+    libcxxabi = llvmPackage.libraries.libcxxabi;
+
+  buildInputs = [
+    pkgs.hello
+    pkgs.cmake
+    llvmPackage.libcxxClang
+    pkgs.SDL2
+    pkgs.capstone
+    pkgs.ninja
+    pkgs.shaderc
+    pkgs.pkg-config
+    pkgs.dbus
+    pkgs.bzip2
+    pkgs.gdb
+    pkgs.vulkan-loader
+    stdenv
+    libcxx
+    libcxxabi
+  ];
+in
+pkgs.mkShell {
+  buildInputs = buildInputs;
+  shellHook = ''
+    export CPATH=$CPATH:${libcxx.dev}/include/c++/v1
+    export CPLUS_INCLUDE_PATH=$CPATH
+    export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:${libcxx}/lib:${libcxxabi}/lib
+  '';
+  CPATH = pkgs.lib.makeSearchPathOutput "dev" "include" (buildInputs);
+}