extract log persistence config from s6 to new module

because it frobs kernel config, it breaks levitate
as levitate evalModules doesn't include the kernel

default.nix

@@ -33,6 +33,7 @@ let
       ./modules/busybox.nix
       ./modules/hostname.nix
       ./modules/kernel
+      ./modules/logging.nix
       ./modules/klogd.nix
       device.module
       liminix-config

modules/logging.nix

@@ -0,0 +1,19 @@
+{ config, lib, ... }:
+let
+  inherit (lib) mkIf mkEnableOption mkOption types;
+in {
+  options = {
+    logging = {
+      persistent = {
+        enable = mkEnableOption "store logs across reboots";
+      };
+    };
+  };
+   config = {
+     kernel.config = mkIf config.logging.persistent.enable {
+       PSTORE = "y";
+       PSTORE_PMSG = "y";
+       PSTORE_RAM = "y";
+     };
+   };
+}

modules/s6/default.nix

@@ -17,7 +17,7 @@ let
   logger =
     let pipecmds =
           ["${s6}/bin/s6-log -bpd3 -- ${cfg.script} 1"] ++
-          (lib.optional cfg.persistent.enable
+          (lib.optional (cfg ? persistent && cfg.persistent.enable)
             "/bin/tee /dev/pmsg0") ++
           (lib.optional cfg.shipping.enable
             "${pkgs.logshipper}/bin/logtap ${cfg.shipping.socket} logshipper-socket-event");
@@ -215,9 +215,6 @@ let
 in {
   options = {
     logging = {
-      persistent = {
-        enable = mkEnableOption "store logs across reboots";
-      };
       shipping = {
         enable = mkEnableOption "unix socket for log shipping";
         socket = mkOption {
@@ -269,11 +266,6 @@ in {
     )];
 
   config = {
-    kernel.config = mkIf config.logging.persistent.enable {
-      PSTORE = "y";
-      PSTORE_PMSG = "y";
-      PSTORE_RAM = "y";
-    };
     filesystem = dir {
       etc = dir {
         s6-rc = dir {