xcursor: new module for configuring X cursor theme

modules/modules.nix

@@ -64,6 +64,7 @@ let
     ./services/window-managers/xmonad.nix
     ./services/xscreensaver.nix
     ./systemd.nix
+    ./xcursor.nix
     ./xresources.nix
     ./xsession.nix
     <nixpkgs/nixos/modules/misc/assertions.nix>

modules/xcursor.nix

@@ -0,0 +1,72 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+
+  cfg = config.xcursor;
+
+  cursorType = types.submodule {
+    options = {
+      package = mkOption {
+        type = types.package;
+        example = literalExample "pkgs.vanilla-dmz";
+        description = "Package providing the cursor theme.";
+      };
+
+      name = mkOption {
+        type = types.str;
+        example = "Vanilla-DMZ";
+        description = "The cursor name within the package.";
+      };
+
+      size = mkOption {
+        type = types.int;
+        default = 32;
+        example = 64;
+        description = "The cursor size.";
+      };
+    };
+  };
+
+in
+
+{
+  meta.maintainers = [ maintainers.league ];
+
+  options = {
+    xcursor = mkOption {
+      type = types.nullOr cursorType;
+      default = null;
+      description = ''
+        The X cursor theme to use.
+      '';
+    };
+  };
+
+  config = mkIf (cfg != null) {
+
+    home.packages = [cfg.package];
+
+    xsession.initExtra = ''
+      ${pkgs.xorg.xsetroot}/bin/xsetroot -xcf ${cfg.package}/share/icons/${cfg.name}/cursors/X_cursor ${toString cfg.size}
+    '';
+
+    xresources.properties = {
+      "Xcursor.theme" = cfg.name;
+      "Xcursor.size"  = cfg.size;
+    };
+
+    gtk.gtk2.extraConfig = ''
+      gtk-cursor-theme-name="${cfg.name}"
+      gtk-cursor-theme-size=${toString cfg.size}
+    '';
+
+    gtk.gtk3.extraConfig = {
+      "gtk-cursor-theme-name" = cfg.name;
+      "gtk-cursor-theme-size" = cfg.size;
+    };
+
+
+  };
+}