Revert "remove references to stdenv and replace with lib"

This reverts commit 0dd9ecdafe.

pkgs/tubslatex/default.nix

@@ -1,6 +1,5 @@
-{ lib, fetchzip, unzip }:
-with lib;
-mkDerivation rec {
+{ stdenv, fetchzip, unzip }:
+stdenv.mkDerivation rec {
   src = ./tubslatex_1.3.2.tds.zip;
   sourceRoot = ".";
   nativeBuildInputs = [ unzip ];