fix opencv not working in devshell flake

.envrc

@@ -0,0 +1 @@
+use flake

flake.nix

@@ -0,0 +1,53 @@
+{
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+    rust-overlay.url = "github:oxalica/rust-overlay";
+  };
+
+  outputs = { self, nixpkgs, rust-overlay, flake-utils, ... }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        overlays = [ (import rust-overlay) ];
+        pkgs = import nixpkgs {
+          inherit system overlays;
+        };
+      in
+      {
+        devShells.default = pkgs.mkShell {
+          #LIBCLANG_PATH = "${pkgs.libclang.lib}/lib";
+          #BINDGEN_EXTRA_CLANG_ARGS = "-isystem ${pkgs.libclang.lib}/lib/clang/${flake-utils.lib.getVersion pkgs.clang}/include";
+
+          buildInputs = with pkgs; [
+            rust-bin.stable.latest.default
+            rust-bin.stable.latest.rustfmt
+            rust-bin.stable.latest.clippy
+          ];
+          nativeBuildInputs = [
+              pkgs.pkg-config
+              pkgs.cmake
+              pkgs.vcpkg
+          ];
+            packages = with pkgs; [
+                rust-analyzer
+                pkg-config
+                opencv
+                alsa-lib
+                systemdLibs
+                cmake
+                fontconfig
+                linuxHeaders
+                rustPlatform.bindgenHook
+                llvmPackages.libclang.lib
+                llvmPackages.clang
+            ];
+            LIBCLANG_PATH = "${pkgs.llvmPackages.libclang.lib}/lib";
+            shellHook = ''
+              export LIBCLANG_PATH = "${pkgs.llvmPackages.libclang.lib}/lib";
+              cargo version
+            '';
+
+        };
+      }
+    );
+}