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/ocaml-modules/janestreet/ppx-optcomp.nix

@@ -1,4 +1,4 @@
-{stdenv, buildOcamlJane,
+{lib, stdenv, buildOcamlJane,
  ppx_core, ppx_tools}:
 
 buildOcamlJane {
@@ -7,7 +7,7 @@ buildOcamlJane {
   propagatedBuildInputs =
     [ ppx_core ppx_tools ];
 
-  meta = with stdenv.lib; {
+  meta = with lib; {
     description = "ppx_optcomp stands for Optional Compilation. It is a tool used to handle optional compilations of pieces of code depending of the word size, the version of the compiler, etc.";
     maintainers = [ maintainers.maurer ];
     license = licenses.asl20;