flake-parts/setups: add specialArgs to each builder function

It's only there in its raw function but we probably don't want to expose
this especially that it will make integration for each to be a pain to
implement. For now, it will just sit and exist and being reconsidered
and reverted at some point if it isn't.

modules/flake-parts/setups/home-manager.nix

@@ -12,12 +12,13 @@ let
     , nixpkgsBranch ? "nixpkgs"
     , homeManagerBranch ? "home-manager"
     , extraModules ? [ ]
+    , specialArgs ? { }
     }:
     let
       pkgs = inputs.${nixpkgsBranch}.legacyPackages.${system};
     in
     inputs.${homeManagerBranch}.lib.homeManagerConfiguration {
-      extraSpecialArgs = {
+      extraSpecialArgs = specialArgs // {
         foodogsquaredModulesPath = builtins.toString homeManagerModules;
       };
 

modules/flake-parts/setups/nixos.nix

@@ -13,7 +13,7 @@ let
   partsConfig = config;
 
   # A thin wrapper around the NixOS configuration function.
-  mkHost = { extraModules ? [ ], nixpkgsBranch ? "nixpkgs", system }:
+  mkHost = { system ,extraModules ? [ ], nixpkgsBranch ? "nixpkgs", specialArgs ? { } }:
     let
       nixpkgs = inputs.${nixpkgsBranch};
 
@@ -25,7 +25,7 @@ let
       nixosSystem = args: import "${nixpkgs}/nixos/lib/eval-config.nix" args;
     in
     (lib.makeOverridable nixosSystem) {
-      specialArgs = {
+      specialArgs = specialArgs // {
         foodogsquaredUtils = import ../../../lib/utils/nixos.nix { inherit lib; };
         foodogsquaredModulesPath = builtins.toString nixosModules;
       };

modules/flake-parts/setups/nixvim.nix

@@ -9,13 +9,19 @@ let
   cfg = config.setups.nixvim;
   nixvimModules = ../../nixvim;
 
-  mkNixvimConfig = { system, pkgs, nixvimBranch ? "nixvim", modules ? [ ] }:
+  mkNixvimConfig = {
+    system,
+    pkgs,
+    nixvimBranch ? "nixvim",
+    modules ? [ ],
+    specialArgs ? { },
+  }:
     inputs.${nixvimBranch}.legacyPackages.${system}.makeNixvimWithModule {
       inherit pkgs;
       module = {
         imports = modules;
       };
-      extraSpecialArgs = {
+      extraSpecialArgs = specialArgs // {
         foodogsquaredModulesPath = builtins.toString nixvimModules;
       };
     };