systemd: fix ukify script

The script requires a python3 shebang with an environment that includes
python3Packages.pefile at runtime.

pkgs/os-specific/linux/systemd/default.nix

@@ -117,6 +117,7 @@
 , withTimedated ? true
 , withTimesyncd ? true
 , withTpm2Tss ? true
+, withUkify ? false  # adds python to closure which is too much by default
 , withUserDb ? true
 , withUtmp ? !stdenv.hostPlatform.isMusl
   # tests assume too much system access for them to be feasible for us right now
@@ -349,7 +350,7 @@ stdenv.mkDerivation (finalAttrs: {
   # when cross-compiling.
   + ''
     shopt -s extglob
-    patchShebangs tools test src/!(rpm|kernel-install) src/kernel-install/test-kernel-install.sh
+    patchShebangs tools test src/!(rpm|kernel-install|ukify) src/kernel-install/test-kernel-install.sh
   '';
 
   outputs = [ "out" "man" "dev" ];
@@ -414,6 +415,7 @@ stdenv.mkDerivation (finalAttrs: {
     ++ lib.optionals (withHomed || withCryptsetup) [ libfido2 ]
     ++ lib.optionals withLibBPF [ libbpf ]
     ++ lib.optional withTpm2Tss tpm2-tss
+    ++ lib.optional withUkify (python3Packages.python.withPackages (ps: with ps; [ pefile ]))
   ;
 
   #dontAddPrefix = true;
@@ -510,11 +512,10 @@ stdenv.mkDerivation (finalAttrs: {
     # more frequent development builds
     "-Dman=true"
 
-    # Temporary disable the ukify tool. see https://github.com/NixOS/nixpkgs/pull/216826#issuecomment-1465228824
-    "-Dukify=false"
-
     "-Defi=${lib.boolToString withEfi}"
     "-Dgnu-efi=${lib.boolToString withEfi}"
+
+    "-Dukify=${lib.boolToString withUkify}"
   ] ++ lib.optionals withEfi [
     "-Defi-libdir=${toString gnu-efi}/lib"
     "-Defi-includedir=${toString gnu-efi}/include/efi"