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/pygtk/default.nix

@@ -1,4 +1,4 @@
-{ stdenv, fetchurl, fetchpatch, python, pkgconfig, gtk2, pygobject2, pycairo, pango
+{ lib, stdenv, fetchurl, fetchpatch, python, pkgconfig, gtk2, pygobject2, pycairo, pango
 , buildPythonPackage, libglade ? null, isPy3k }:
 
 buildPythonPackage rec {
@@ -65,7 +65,7 @@ buildPythonPackage rec {
                   $out/lib/${python.libPrefix}/site-packages/${pname}-${version}.pth
   '';
 
-  meta = with stdenv.lib; {
+  meta = with lib; {
     description = "GTK 2 Python bindings";
     homepage = "https://gitlab.gnome.org/Archive/pygtk";
     platforms = platforms.all;