devshell: init with gnumake for new make roles target

.envrc

@@ -0,0 +1,13 @@
+#!/usr/bin/env bash
+# ^ added for shellcheck and file-type detection
+
+# Watch & reload direnv on change
+cd devshell || exit
+watch_file devshell.toml
+
+if [[ $(type -t use_flake) != function ]]; then
+  echo "ERROR: use_flake function missing."
+  echo "Please update direnv to v2.30.0 or later."
+  exit 1
+fi
+use flake

devshell/.gitignore

@@ -0,0 +1 @@
+/.direnv/

devshell/devshell.toml

@@ -0,0 +1,4 @@
+# https://numtide.github.io/devshell
+[[commands]]
+package = "devshell.cli"
+help = "Per project developer environments"

devshell/flake.lock

@@ -0,0 +1,92 @@
+{
+  "nodes": {
+    "devshell": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      },
+      "locked": {
+        "lastModified": 1667210711,
+        "narHash": "sha256-IoErjXZAkzYWHEpQqwu/DeRNJGFdR7X2OGbkhMqMrpw=",
+        "owner": "numtide",
+        "repo": "devshell",
+        "rev": "96a9dd12b8a447840cc246e17a47b81a4268bba7",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "devshell",
+        "type": "github"
+      }
+    },
+    "flake-utils": {
+      "locked": {
+        "lastModified": 1642700792,
+        "narHash": "sha256-XqHrk7hFb+zBvRg6Ghl+AZDq03ov6OshJLiSWOoX5es=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "846b2ae0fc4cc943637d3d1def4454213e203cba",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "flake-utils_2": {
+      "locked": {
+        "lastModified": 1667395993,
+        "narHash": "sha256-nuEHfE/LcWyuSWnS8t12N1wc105Qtau+/OdUAjtQ0rA=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "5aed5285a952e0b949eb3ba02c12fa4fcfef535f",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1643381941,
+        "narHash": "sha256-pHTwvnN4tTsEKkWlXQ8JMY423epos8wUOhthpwJjtpc=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "5efc8ca954272c4376ac929f4c5ffefcc20551d5",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs_2": {
+      "locked": {
+        "lastModified": 1667969101,
+        "narHash": "sha256-GL53T705HO7Q/KVfbb5STx8AxFs8YgaGY8pvAZC+O7U=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "bbf77421ac51a7c93f5f0f760da99e4dbce614fa",
+        "type": "github"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "type": "indirect"
+      }
+    },
+    "root": {
+      "inputs": {
+        "devshell": "devshell",
+        "flake-utils": "flake-utils_2",
+        "nixpkgs": "nixpkgs_2"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

devshell/flake.nix

@@ -0,0 +1,23 @@
+{
+  description = "virtual environments";
+
+  inputs.devshell.url = "github:numtide/devshell";
+  inputs.flake-utils.url = "github:numtide/flake-utils";
+
+  outputs = { self, flake-utils, devshell, nixpkgs }:
+    flake-utils.lib.eachDefaultSystem (system: {
+      devShell =
+        let pkgs = import nixpkgs {
+          inherit system;
+
+          overlays = [ devshell.overlay ];
+        };
+        in
+        pkgs.devshell.mkShell {
+          imports = [ (pkgs.devshell.importTOML ./devshell.toml) ];
+          devshell.packages = with pkgs; [
+            gnumake
+          ];
+        };
+    });
+}