sile: make it easier to setup a modified luaEnv when writing documents

  enableParallelBuilding = true;

  passthru = {

    luaEnv = lua.withPackages (

      ps:

      with ps;

    # Use this passthru variable to add packages to your lua environment. Use

    # something like this in your development environment:

    #

    # myLuaEnv = lua.withPackages (

    #  ps: lib.attrVals (sile.passthru.luaPackages ++ [

    #    "lua-cjson"

    #    "lua-resty-http"

    #  ]) ps

    # )

    luaPackages =

      [

        cassowary

        cldr

        fluent

        linenoise

        loadkit

        lpeg

        lua-zlib

        lua_cliargs

        luaepnf

        luaexpat

        luafilesystem

        luarepl

        luasec

        luasocket

        luautf8

        penlight

        vstruct

        "cassowary"

        "cldr"

        "fluent"

        "linenoise"

        "loadkit"

        "lpeg"

        "lua-zlib"

        "lua_cliargs"

        "luaepnf"

        "luaexpat"

        "luafilesystem"

        "luarepl"

        "luasec"

        "luasocket"

        "luautf8"

        "penlight"

        "vstruct"

        # lua packages needed for testing

        busted

        luacheck

        "busted"

        "luacheck"

        # packages needed for building api docs

        ldoc

        "ldoc"

        # NOTE: Add lua packages here, to change the luaEnv also read by `flake.nix`

      ]

      ++ lib.optionals (lib.versionOlder lua.luaversion "5.2") [

        bit32

        "bit32"

      ]

      ++ lib.optionals (lib.versionOlder lua.luaversion "5.3") [

        compat53

      ]

    );

        "compat53"

      ];

    luaEnv = lua.withPackages (ps: lib.attrVals finalAttrs.finalPackage.passthru.luaPackages ps);

    # Copied from Makefile.am

    tests.test = lib.optionalAttrs (!(stdenv.hostPlatform.isDarwin && stdenv.hostPlatform.isAarch64)) (