make-disk-image: also use xcp

Author: Mic92

lib/make-disk-image.nix

@@ -92,6 +92,7 @@ let
       util-linux
       findutils
       kmod
+      xcp
     ]
     ++ cfg.extraDependencies;
   preVM = ''
@@ -143,7 +144,7 @@ let
 
     # We copy files with cp because `nix copy` seems to have a large memory leak
     mkdir -p ${systemToInstall.config.disko.rootMountPoint}/nix/store
-    time xargs cp --recursive --target ${systemToInstall.config.disko.rootMountPoint}/nix/store < ${closureInfo}/store-paths
+    xargs xcp --recursive --target-directory ${systemToInstall.config.disko.rootMountPoint}/nix/store < ${closureInfo}/store-paths
 
     ${systemToInstall.config.system.build.nixos-install}/bin/nixos-install --root ${systemToInstall.config.disko.rootMountPoint} --system ${systemToInstall.config.system.build.toplevel} --keep-going --no-channel-copy -v --no-root-password --option binary-caches ""
     umount -Rv ${lib.escapeShellArg systemToInstall.config.disko.rootMountPoint}