Add direnv support and fix missing dependencies

default.nix

+{ pkgs ? import <nixpkgs> {} }:
+
+rec {
+
+  latex = pkgs.texlive.combine {
+    inherit (pkgs.texlive)
+      collection-basic
+      collection-fontsextra
+      collection-fontsrecommended
+      collection-fontutils
+      collection-langenglish
+      collection-langgerman
+      collection-latex
+      collection-latexextra
+      collection-latexrecommended
+      collection-luatex
+      collection-mathscience
+      scheme-medium
+    ;
+  };
+
+  shell = pkgs.mkShell {
+    buildInputs = with pkgs; [
+      git
+      gnumake
+      latex
+    ];
+  };
+
+  envrc = pkgs.writeText "envrc" ''
+    PATH_add ${latex}/bin
+    PATH_add ${pkgs.git}/bin
+    PATH_add ${pkgs.gnumake}/bin
+  '';
+
+}

shell.nix

 { pkgs ? import <nixpkgs> {} }:
 
-let
-
-  latex = pkgs.texlive.combine {
-    inherit (pkgs.texlive)
-      collection-basic
-      collection-fontsextra
-      collection-fontsrecommended
-      collection-fontutils
-      collection-langenglish
-      collection-langgerman
-      collection-latex
-      collection-latexextra
-      collection-latexrecommended
-      collection-luatex
-      collection-mathscience
-      scheme-medium
-    ;
-  };
-
-in pkgs.mkShell {
-  buildInputs = with pkgs; [
-    gnumake
-    latex
-  ];
-}
+(import ./. {inherit pkgs;}).shell