Merge master into haskell-updates

# Using Nixpkgs {#part-using}

```{=include=} chapters

using/platform-support.chapter.md

using/configuration.chapter.md

using/overlays.chapter.md

using/overrides.chapter.md

# Platform Support {#chap-platform-support}

Packages receive varying degrees of support, both in terms of maintainer attention and available computation resources for continuous integration (CI).

Below is the list of the best supported platforms:

- `x86_64-linux`: Highest level of support.

- `aarch64-linux`: Well supported, with most packages building successfully in CI.

- `aarch64-darwin`: Receives better support than `x86_64-darwin`.

- `x86_64-darwin`: Receives some support.

There are many other platforms with varying levels of support.

The provisional platform list in [Appendix A] of [RFC046], while not up to date, can be used as guidance.

A more formal definition of the platform support tiers is provided in [RFC046], but has not been fully implemented yet.

[RFC046]: https://github.com/NixOS/rfcs/blob/master/rfcs/0046-platform-support-tiers.md

[Appendix A]: https://github.com/NixOS/rfcs/blob/master/rfcs/0046-platform-support-tiers.md#appendix-a-non-normative-description-of-platforms-in-november-2019

    fullName = "Eiffel Forum License v2.0";

  };

  elastic = {

    fullName = "ELASTIC LICENSE";

    url = "https://github.com/elastic/elasticsearch/blob/master/licenses/ELASTIC-LICENSE.txt";

  elastic20 = {

    fullName = "Elastic License 2.0";

    url = "https://github.com/elastic/elasticsearch/blob/main/licenses/ELASTIC-LICENSE-2.0.txt";

    free = false;

  };

    fullName = "University of Illinois/NCSA Open Source License";

  };

  ncul1 = {

    spdxId = "NCUL1";

    fullName = "Netdata Cloud UI License v1.0";

    free = false;

    redistributable = true; # Only if used in Netdata products.

    url = "https://raw.githubusercontent.com/netdata/netdata/master/web/gui/v2/LICENSE.md";

  };

  nlpl = {

    spdxId = "NLPL";

    fullName = "No Limit Public License";

- `python3.pkgs.flitBuildHook` has been removed. Use `flit-core` and `format = "pyproject"` instead.

- The `qemu-vm.nix` module now supports disabling overriding `fileSystems` with

  `virtualisation.fileSystems`. This enables the user to boot VMs from

  "external" disk images not created by the qemu-vm module. You can stop the

  qemu-vm module from overriding `fileSystems` by setting

  `virtualisation.fileSystems = lib.mkForce { };`.

- The `electron` packages now places its application files in `$out/libexec/electron` instead of `$out/lib/electron`. Packages using electron-builder will fail to build and need to be adjusted by changing `lib` to `libexec`.

        plocate = (mkIf isPLocate (mkMerge [ common plocate ]));

      };

    environment.systemPackages = [ (cfg.locate.override { dbfile = cfg.output; }) ];

    environment.systemPackages = [ cfg.locate ];

    environment.variables = mkIf (!isMorPLocate) { LOCATE_PATH = cfg.output; };

    environment.variables.LOCATE_PATH = cfg.output;

    environment.etc = {

      # write /etc/updatedb.conf for manual calls to `updatedb`