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/mypy/default.nix

@@ -1,4 +1,4 @@
-{ stdenv, fetchFromGitHub, buildPythonPackage, typed-ast, psutil, isPy3k
+{ lib, stdenv, fetchFromGitHub, buildPythonPackage, typed-ast, psutil, isPy3k
 , mypy-extensions
 , typing-extensions
 , fetchpatch
@@ -56,7 +56,7 @@ buildPythonPackage rec {
   # is64bit: unfortunately the build would exhaust all possible memory on i686-linux.
   MYPY_USE_MYPYC = stdenv.buildPlatform.is64bit;
 
-  meta = with stdenv.lib; {
+  meta = with lib; {
     description = "Optional static typing for Python";
     homepage    = "http://www.mypy-lang.org";
     license     = licenses.mit;

pkgs/development/python-modules/mypy/extensions.nix

@@ -1,4 +1,4 @@
-{ stdenv, fetchPypi, buildPythonPackage, typing, pythonOlder }:
+{ lib, stdenv, fetchPypi, buildPythonPackage, typing, pythonOlder }:
 
 buildPythonPackage rec {
   pname = "mypy-extensions";
@@ -15,7 +15,7 @@ buildPythonPackage rec {
 
   propagatedBuildInputs = if pythonOlder "3.5" then [ typing ] else [ ];
 
-  meta = with stdenv.lib; {
+  meta = with lib; {
     description = "Experimental type system extensions for programs checked with the mypy typechecker";
     homepage    = "http://www.mypy-lang.org";
     license     = licenses.mit;