anchor.diff:      in  anyMatch (attrs.meta.platforms or lib.platforms.all) &&
         ! anyMatch (attrs.meta.badPlatforms or []);
   
  +  checkOutputsToInstall = attrs: let
  +      expectedOutputs = attrs.meta.outputsToInstall or [];
  +      actualOutputs = attrs.outputs or [ "out" ];
  +      missingOutputs = builtins.filter (output: ! builtins.elem output actualOutputs) expectedOutputs;
  +    in if shouldCheckMeta
  +       then builtins.length missingOutputs > 0
  +       else false;
  +
     # Check if a derivation is valid, that is whether it passes checks for
     # e.g brokenness or license.
     #
  
positive.code:     unsupported = remediate_whitelist "UnsupportedSystem";
      blacklisted = x: "";
      insecure = remediate_insecure;
      unknown-meta = x: "";
    };
    remediate_whitelist = allow_attr: attrs:
  
negative.code:       { valid = false; reason = "unsupported"; errormsg = "is not supported on ‘${hostPlatform.config}’"; }
      else if !(hasAllowedInsecure attrs) then
        { valid = false; reason = "insecure"; errormsg = "is marked as insecure"; }
      else if checkOutputsToInstall attrs then
        { valid = false; reason = "broken-outputs"; errormsg = "has invalid meta.outputsToInstall"; }
      else let res = checkMeta (attrs.meta or {}); in if res != [] then
        { valid = false; reason = "unknown-meta"; errormsg = "has an invalid meta attrset:${lib.concatMapStrings (x: "\n\t - " + x) res}"; }
      else { valid = true; };
  