initialise fonts module

default.nix

@@ -43,6 +43,7 @@ let
         ./modules/nix/nix-info.nix
         ./modules/nix/nixpkgs.nix
         ./modules/environment
+        ./modules/fonts
         ./modules/launchd
         ./modules/services/activate-system
         ./modules/services/buildkite-agent.nix

modules/fonts/default.nix

@@ -0,0 +1,40 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.fonts;
+in {
+  options = {
+    fonts = {
+      enableFontDir = mkOption {
+        default = false;
+        description = ''
+          Whether to create a directory with links to all fonts in
+          <filename>/run/current-system/sw/share/fonts</filename>.
+        '';
+      };
+      fonts = mkOption {
+        type = types.listOf types.path;
+        default = [];
+        example = literalExample "[ pkgs.dejavu_fonts ]";
+        description = "List of primary font paths.";
+      };
+    };
+  };
+  
+  config = mkIf cfg.enableFontDir {
+    system.build.fonts = pkgs.buildEnv {
+      name = "system-fonts";
+      paths = cfg.fonts;
+      pathsToLink = "/share/fonts/truetype";
+    };
+    system.activationScripts.fonts.text = ''
+      # Set up fonts.
+      echo "setting up fonts..." >&2
+      /bin/ln -hf ${config.system.build.fonts}/share/fonts/truetype/* /Library/Fonts/
+      '';
+    environment.pathsToLink = [ "/share/fonts/truetype" ];
+  };
+
+}

modules/system/activation-scripts.nix

@@ -64,6 +64,7 @@ in
       ${cfg.activationScripts.time.text}
       ${cfg.activationScripts.networking.text}
       ${cfg.activationScripts.keyboard.text}
+      ${cfg.activationScripts.fonts.text}
 
       ${cfg.activationScripts.postActivation.text}