fix gc scheduling for Linux and Mac (read systemd & launchd) that uses

different formats.

nix/system/common/nix.nix

@@ -21,11 +21,6 @@
 
     gc = {
       automatic = true;
-      interval = {
-        Weekday = 0;
-        Hour = 0;
-        Minute = 0;
-      };
       options = "--delete-older-than 7d";
     };
   };

nix/system/darwin.nix

@@ -9,6 +9,11 @@ let
   utils = import ../utils.nix;
 in
 {
+  nix.gc.interval = {
+    Weekday = 0;
+    Hour = 0;
+    Minute = 0;
+  };
 
   environment.systemPackages = with pkgs; [
     home-manager

nix/system/linux.nix

@@ -4,6 +4,8 @@
     ./hardware-configuration.nix
   ];
 
+  nix.gc.dates = "weekly";
+
   programs = {
     xwayland.enable = true;
     sway = {