Make git config nix-darwin-aware

modules/futureware.nix

@@ -1,15 +1,19 @@
 # This module is supposed to be used on internal FutureWare servers.
 
-{
+{ lib, options, ... }:
-  programs.git.enable = true;
+
-  programs.git.config = {
+let
+  gitConfig = {
     url."https://git.sheremet.ch/futureware-tech/nix.git".insteadOf =
       "https://github.com/futureware-tech/nix.git";
     url."https://git.sheremet.ch/artem/dotfiles.git".insteadOf =
       "https://github.com/dotdoom/dotfiles.git";
     url."https://git.sheremet.ch/home/esphome.git".insteadOf = "https://github.com/dotdoom/esphome.git";
   };
-
+  hasGitOption = options ? programs.git;
+in
+lib.mkMerge [
+  {
     nix.settings = {
       substituters = [
         "http://nix-cache.home.arpa"
@@ -21,3 +25,14 @@
       ];
     };
   }
+
+  (lib.mkIf hasGitOption {
+    programs.git.enable = true;
+    programs.git.config = gitConfig;
+  })
+
+  (lib.mkIf (!hasGitOption) {
+    # nix-darwin
+    environment.etc."gitconfig".text = lib.generators.toGitINI gitConfig;
+  })
+]