overlays: Add base16-schemes

Necessary since an update caused the YAML structure to change. Will be
able to remove this once the Qt pull request for stylix gets merged
upstream.

Old: 2b6f2d0677/3024.yaml
New: ae4ce8b0d1/base16/3024.yaml

overlays/base16-schemes.nix

@@ -0,0 +1,25 @@
+{
+  nixpkgs.overlays = [
+    (final: prev: {
+      base16-schemes = prev.base16-schemes.overrideAttrs (oldAttrs: {
+        version = "unstable-2023-05-02";
+
+        src = prev.fetchFromGitHub {
+          owner = "tinted-theming";
+          repo = "base16-schemes";
+          rev = "9a4002f78dd1094c123169da243680b2fda3fe69";
+          hash = "sha256-AngNF++RZQB0l4M8pRgcv66pAcIPY+cCwmUOd+RBJKA=";
+        };
+
+        installPhase = ''
+          runHook preInstall
+
+          mkdir -p $out/share/themes/
+          install *.yaml $out/share/themes/
+
+          runHook postInstall
+        '';
+      });
+    })
+  ];
+}

overlays/default.nix

@@ -1,6 +1,7 @@
 {
   imports = [
     ./alejandra.nix
+    ./base16-schemes.nix
     ./eza.nix
     ./kitty.nix
     ./zola.nix