Merge pull request #264811 from emilylange/systemd-empty-unit-build

      pkgs.runCommand "unit-${mkPathSafeName name}"

        { preferLocalBuild = true;

          allowSubstitutes = false;

          inherit (unit) text;

          # unit.text can be null. But variables that are null listed in

          # passAsFile are ignored by nix, resulting in no file being created,

          # making the mv operation fail.

          text = optionalString (unit.text != null) unit.text;

          passAsFile = [ "text" ];

        }

        ''