nix: replace pkgs.system with pkgs.stdenv.hostPlatform.system

evaluation warning: ‘system’ has been renamed to/replaced by ‘stdenv.hostPlatform.system’

nixosModules/default.nix

@@ -30,6 +30,7 @@
     };
     userbornConfigJson = pkgs.writeText "userborn.json" (builtins.toJSON userbornConfig);
     userbornResults = pkgs.runCommand "baked userborn" {} "mkdir -p $out; ${lib.getExe pkgs.userborn} ${userbornConfigJson} $out";
+  system = pkgs.stdenv.hostPlatform.system;
 in {
   boot.isContainer = true;
   fileSystems."/".device = lib.mkDefault "/dev/sda"; # dummy
@@ -222,7 +223,7 @@ in {
     requires = ["wayland-proxy-virtwl.socket"];
     serviceConfig = {
       ExecStartPre = "+/run/current-system/sw/bin/chmod 0666 /dev/dri/card0 /dev/dri/renderD128";
-      ExecStart = "${virtwl.packages.${pkgs.system}.proxy}/bin/wayland-proxy-virtwl --virtio-gpu";
+      ExecStart = "${virtwl.packages.${system}.proxy}/bin/wayland-proxy-virtwl --virtio-gpu";
       Environment = ["XDG_RUNTIME_DIR=${runtimeDir}"];
       User = "appvm";
       Group = "appvm";
@@ -246,12 +247,12 @@ in {
     requires = ["sidebus-agent.socket"];
     serviceConfig = {
       ImportCredential = "sidebus.port";
-      ExecStart = "${sidebus.packages.${pkgs.system}.sidebus-agent}/bin/sidebus-agent";
+      ExecStart = "${sidebus.packages.${system}.sidebus-agent}/bin/sidebus-agent";
       User = "appvm";
       Group = "appvm";
     };
   };
 
   hardware.graphics.enable = true;
-  hardware.graphics.package = self.packages.${pkgs.system}.mesa;
+  hardware.graphics.package = self.packages.${system}.mesa;
 }

nixosModules/testvm.nix

@@ -6,7 +6,7 @@
   environment.systemPackages = [
     pkgs.fastfetch
     pkgs.htop
-    virtwl.packages.${pkgs.system}.proxy
+    virtwl.packages.${pkgs.stdenv.hostPlatform.system}.proxy
     pkgs.wayland-utils
     pkgs.weston
     pkgs.waycheck