libgpiod: fix Python bindings

libgpiod's Python bindings no longer worked after the upgrade to 2.0.1. The
build system installs an egg, which doesn't work in nixpkgs. To fix this, I
adopted the same approach I took in #204884. This patch builds the Python
bindings as a separate package, using the normal nixpkgs Python infrastructure.
Besides fixing the bindings, this has the added benefit of avoiding the need to
build a redundant copy of libgpiod as part of the Python bindings package.

Lastly, I cleaned up the libgpiod package a bit, removing an unused dependency
on kmod and an unnecessary configure flag. I also added the full list of
licenses that apply to the package.

pkgs/development/libraries/libgpiod/default.nix

@@ -1,6 +1,5 @@
-{ lib, stdenv, fetchurl, autoreconfHook, autoconf-archive, pkg-config, kmod
-, enable-tools ? true
-, enablePython ? false, python3, ncurses }:
+{ lib, stdenv, fetchurl, autoreconfHook, autoconf-archive, pkg-config
+, enable-tools ? true }:
 
 stdenv.mkDerivation rec {
   pname = "libgpiod";
@@ -11,7 +10,6 @@ stdenv.mkDerivation rec {
     hash = "sha256-tu2lU1YWCo5zkG49SOlZ74EpZ4fXZJdbEPJX6WYGaOk=";
   };
 
-  buildInputs = [ kmod ] ++ lib.optionals enablePython [ python3 ncurses ];
   nativeBuildInputs = [
     autoconf-archive
     pkg-config
@@ -21,8 +19,7 @@ stdenv.mkDerivation rec {
   configureFlags = [
     "--enable-tools=${if enable-tools then "yes" else "no"}"
     "--enable-bindings-cxx"
-    "--prefix=${placeholder "out"}"
-  ] ++ lib.optional enablePython "--enable-bindings-python";
+  ];
 
   meta = with lib; {
     description = "C library and tools for interacting with the linux GPIO character device";
@@ -32,7 +29,10 @@ stdenv.mkDerivation rec {
       data structures behind a straightforward API.
     '';
     homepage = "https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git/about/";
-    license = licenses.lgpl2;
+    license = with licenses; [
+      lgpl21Plus # libgpiod
+      lgpl3Plus # C++ bindings
+    ] ++ lib.optional enable-tools gpl2Plus;
     maintainers = [ maintainers.expipiplus1 ];
     platforms = platforms.linux;
   };

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

@@ -0,0 +1,25 @@
+{ lib
+, buildPythonPackage
+, libgpiod
+}:
+buildPythonPackage {
+  inherit (libgpiod) pname version src;
+  format = "setuptools";
+
+  buildInputs = [ libgpiod ];
+
+  preConfigure = ''
+    cd bindings/python
+  '';
+
+  # Requires libgpiod built with --enable-tests
+  doCheck = false;
+  pythonImportsCheck = [ "gpiod" ];
+
+  meta = with lib; {
+    description = "Python bindings for libgpiod";
+    homepage = "https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git/about/";
+    license = licenses.lgpl21Plus;
+    maintainers = with maintainers; [ lopsided98 ];
+  };
+}

pkgs/top-level/python-packages.nix

@@ -5846,10 +5846,9 @@ self: super: with self; {
     pythonSupport = true;
   });
 
-  libgpiod = toPythonModule (pkgs.libgpiod.override {
-    enablePython = true;
-    python3 = python;
-  });
+  libgpiod = callPackage ../development/python-modules/libgpiod {
+    inherit (pkgs) libgpiod;
+  };
 
   libgpuarray = callPackage ../development/python-modules/libgpuarray {
     clblas = pkgs.clblas.override { inherit (self) boost; };