anchor.diff:  
         ${concatMapStringsSep "\n" (attr: userLaunchdActivation attr.target) userLaunchAgents}
   
  -      for f in $(ls /run/current-system/user/Library/LaunchAgents); do
  +      for f in $(ls /run/current-system/user/Library/LaunchAgents 2> /dev/null); do
           if test ! -e "${cfg.build.launchd}/user/Library/LaunchAgents/$f"; then
             echo "removing user service $(basename $f .plist)" >&2
             launchctl unload -w ~/Library/LaunchAgents/$f || true
  
positive.code:       ${concatMapStringsSep "\n" (attr: launchdActivation "LaunchAgents" attr.target) launchAgents}
        ${concatMapStringsSep "\n" (attr: launchdActivation "LaunchDaemons" attr.target) launchDaemons}
  
        for f in $(ls /run/current-system/Library/LaunchAgents); do
          if test ! -e "${cfg.build.launchd}/Library/LaunchAgents/$f"; then
            echo "removing service $(basename $f .plist)" >&2
            launchctl unload -w "/Library/LaunchAgents/$f" || true
  
negative.code:         fi
        done
  
        for f in $(ls /run/current-system/Library/LaunchDaemons 2> /dev/null); do
          if test ! -e "${cfg.build.launchd}/Library/LaunchDaemons/$f"; then
            echo "removing service $(basename $f .plist)" >&2
            launchctl unload -w "/Library/LaunchDaemons/$f" || true
  