treewide: with stdenv.lib; in meta -> with lib;

Part of: https://github.com/NixOS/nixpkgs/issues/108938

meta = with stdenv.lib;

is a widely used pattern. We want to slowly remove
the `stdenv.lib` indirection and encourage people
to use `lib` directly. Thus let’s start with the meta
field.

This used a rewriting script to mostly automatically
replace all occurances of this pattern, and add the
`lib` argument to the package header if it doesn’t
exist yet.

The script in its current form is available at
https://cs.tvl.fyi/depot@2f807d7f141068d2d60676a89213eaa5353ca6e0/-/blob/users/Profpatsch/nixpkgs-rewriter/default.nix

pkgs/development/python-modules/lmtpd/default.nix

@@ -1,4 +1,4 @@
-{ buildPythonPackage, fetchPypi, isPy3k, stdenv }:
+{ buildPythonPackage, fetchPypi, isPy3k, lib, stdenv }:
 
 buildPythonPackage rec {
   pname = "lmtpd";
@@ -11,7 +11,7 @@ buildPythonPackage rec {
     sha256 = "2c6825d2ffa1de099440411a742f58e1b3e8deeb3345adcfd4c2c38d4baf62b3";
   };
 
-  meta = with stdenv.lib; {
+  meta = with lib; {
     homepage = "https://github.com/moggers87/lmtpd";
     description = "LMTP counterpart to smtpd in the Python standard library";
     license = licenses.mit;