modules/overlays: Add nixpkgs overlays to NIX_PATH for global use

1 files changed, 20 insertions, 11 deletions

diff --git a/modules/overlays/default.nix b/modules/overlays/default.nix
index 745673a..fa1ee01 100644
--- a/modules/overlays/default.nix
+++ b/modules/overlays/default.nix
@@ -1,17 +1,26 @@
-{ lib, config, ... }:
+{ lib, config, pkgs, ... }:
 
-let cfg = config.this.overlays;
-    overlay = ov:
-      lib.optional cfg."${ov}".enable
-        (import ./${ov}.nix);
+let
+  cfg = config.this.overlays;
+
+  mapOverlays = f:
+    lib.mapAttrsToList (ov: _: f ov)
+      (lib.filterAttrs
+        (ov: c: c.enable)
+        cfg);
+
+  overlayDir = pkgs.linkFarm "nixpkgs-overlays"
+    (mapOverlays (ov: { name = ${ov}.nix; path = ./${ov}.nix; }));
 in
 {
-  options = {
-    this.overlays.emacs.enable = lib.mkEnableOption "custom-built Emacs overlay";
-    this.overlays.g45_h264.enable = lib.mkEnableOption "intel-vaapi-driver with h264 support on gm45";
+  options.this.overlays = {
+    emacs.enable = lib.mkEnableOption "custom-built Emacs overlay";
+    g45_h264.enable = lib.mkEnableOption "intel-vaapi-driver with h264 support on gm45";
   };
 
-  config.nixpkgs.overlays =
-    (overlay "emacs") ++
-    (overlay "g45_h264");
+  config = {
+    nixpkgs.overlays =
+      mapOverlays (ov: import ./${ov}.nix);
+    nix.nixPath = lib.mkAfter ["nixpkgs-overlays=${overlayDir}"];
+  };
 }