nix: add direnv automatic shell

This also enables building the PDF files using `nix build`

.envrc

@@ -0,0 +1,7 @@
+use_flake() {
+  watch_file flake.nix
+  watch_file flake.lock
+  eval "$(nix print-dev-env)"
+}
+
+use flake

flake.lock

@@ -0,0 +1,42 @@
+{
+  "nodes": {
+    "futils": {
+      "locked": {
+        "lastModified": 1610051610,
+        "narHash": "sha256-U9rPz/usA1/Aohhk7Cmc2gBrEEKRzcW4nwPWMPwja4Y=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "3982c9903e93927c2164caa727cd3f6a0e6d14cc",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1614256104,
+        "narHash": "sha256-V92DxPnYqlAr5+eYYhkfdwy6aDVxU8ipVrd1ykWdrE0=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "772406c2a4e22a85620854056a4cd02856fa10f0",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "futils": "futils",
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,55 @@
+{
+  description = "Ambroisie's CV";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs";
+    futils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, nixpkgs, futils } @ inputs:
+    futils.lib.eachSystem futils.lib.allSystems (system:
+      let
+        inherit (nixpkgs) lib;
+        pkgs = nixpkgs.legacyPackages.${system};
+        buildInputs = with pkgs; [
+          gnumake
+          (texlive.combine {
+            inherit (texlive)
+              scheme-small
+              # Build script
+              latexmk
+              # Extra packages needed
+              clearsans
+              fontaxes
+              textpos
+              ifmtarg
+              marvosym
+              ;
+          })
+        ];
+      in
+      {
+        devShell = pkgs.mkShell {
+          name = "cv";
+          inherit buildInputs;
+        };
+
+        defaultPackage = pkgs.stdenvNoCC.mkDerivation {
+          pname = "cv";
+          version = self.rev or "dirty";
+          src = ./.;
+
+          inherit buildInputs;
+
+          buildPhase = ''
+            make
+          '';
+
+          installPhase = ''
+            install -Dm644 en.pdf $out/share/en.pdf
+            install -Dm644 fr.pdf $out/share/fr.pdf
+          '';
+        };
+      }
+    );
+}