nix: set up devShell

Since we're using cgo to call into libacl a few dependencies other than go are required to build.

Signed-off-by: Ophestra Umiker <cat@ophivana.moe>

flake.lock

@@ -0,0 +1,27 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1717179513,
+        "narHash": "sha256-vboIEwIQojofItm2xGCdZCzW96U85l9nDW3ifMuAIdM=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "63dacb46bf939521bdc93981b4cbb7ecb58427a0",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "24.05",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,35 @@
+{
+  description = "ego development environment";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/24.05";
+  };
+
+  outputs = { self, nixpkgs }:
+    let
+      supportedSystems = [ "x86_64-linux" ];
+      forAllSystems = f: nixpkgs.lib.genAttrs supportedSystems (system: f system);
+    in
+    {
+      devShells = forAllSystems
+        (system:
+          let
+            pkgs = import nixpkgs {
+              inherit system;
+            };
+          in
+          {
+            default = with pkgs; mkShell
+              {
+                packages = [
+                  clang
+                  acl
+                  (pkgs.writeShellScriptBin "build" ''
+                    go build -v -ldflags '-s -w -X main.Version=flake'
+                  '')
+                ];
+              };
+          }
+        );
+    };
+}