= Configuring the Build
:page-parent: Development
:page-nav_order: 1
:example-caption: Test

// SPDX-FileCopyrightText: 2022 Unikie
// SPDX-FileCopyrightText: 2023 Alyssa Ross <hi@alyssa.is>
// SPDX-License-Identifier: GFDL-1.3-no-invariants-or-later OR CC-BY-SA-4.0

Some aspects of a Spectrum build can be customised using a build
configuration file.

By default, this configuration file should be called config.nix and located in
the root of the Spectrum source tree, but this can be overridden by setting
`spectrum-config` in the
https://nixos.org/manual/nix/stable/command-ref/env-common.html#env-NIX_PATH[NIX_PATH]
to the path of the configuration file.

The configuration file should contain an attribute set.  See
https://spectrum-os.org/git/spectrum/tree/lib/config.default.nix[lib/config.default.nix]
for supported configuration attributes and their default values.

.config.nix to build Spectrum with a https://nixos.org/manual/nixpkgs/unstable/#sec-overlays-definition[Nixpkgs overlay]
[example]
[source,nix]
----
{ default, ... }:

{
  pkgsArgs = default.pkgsArgs // {
    overlays = [
      (final: super: {
        weston = super.weston.overrideAttrs ({ patches ? [], ... }: {
          patches = patches ++ [
            path/to/weston.patch
          ];
        });
      })
    ] ++ default.pkgsArgs.overlays or [];
  };
}
----