Move to Python 3

[CrumblyLiquid]

Removes the Python 2 dependency in favor of Python 3!
And the changes themselves are pretty small too :)

It seems to build fine with my NixOS flake and it runs the default pebble watchface without issues. Hopefully there aren't any silent breakages.

Details

The original NixOS derivation can be found here

My modified NixOS derivation:

{
  lib, stdenv, fetchFromGitHub, gnumake,
  python3, pkg-config, zlib, glib,
  pixman, dtc,
}:
let
  libraries = [
    zlib
    glib
    pixman
    dtc
    stdenv.cc.cc.lib
  ];

  rpath = lib.makeLibraryPath libraries;
in
stdenv.mkDerivation {
  pname = "qemu-pebble";
  version = "157f3fd";

  src = fetchFromGitHub {
    owner = "CrumblyLiquid";
    repo = "qemu";
    rev = "157f3fd8ceb0d885ed14980d403d73cd5ed8ff42";
    hash = "sha256-gHocmkQkiGOWedr/ufCjpcXJDk/LFylPP6XoNyy6wQw=";
  };

  nativeBuildInputs = [
    gnumake
    python3
    pkg-config
  ]
  ++ libraries;

  LD_LIBRARY_PATH = rpath;

  enableParallelBuilding = true;

  configureFlags = [
    "--disable-werror"
    "--enable-debug"
    "--target-list=arm-softmmu"
    "--extra-cflags=-DSTM32_UART_NO_BAUD_DELAY"
  ];

  postFixup = ''
    patchelf --set-rpath "${rpath}" $out/bin/qemu-system-arm
  '';

  postInstall = ''
    ln -s $out/bin/qemu-system-arm $out/bin/qemu-pebble
  '';
}