anchor.diff:        { valid = false; reason = "blacklisted"; errormsg = "has a blacklisted license (‘${showLicense attrs.meta.license}’)"; }
       else if !allowBroken && attrs.meta.broken or false then
         { valid = false; reason = "broken"; errormsg = "is marked as broken"; }
  -    else if !allowUnsupportedSystem && !allowBroken && attrs.meta.platforms or null != null && !(checkPlatform attrs) then
  +    else if !allowUnsupportedSystem && !allowBroken && !(checkPlatform attrs) then
         { valid = false; reason = "broken"; errormsg = "is not supported on ‘${hostPlatform.config}’"; }
       else if !(hasAllowedInsecure attrs) then
         { valid = false; reason = "insecure"; errormsg = "is marked as insecure"; }
  
positive.code:   checkMeta = meta: if shouldCheckMeta then lib.remove null (lib.mapAttrsToList checkMetaAttr meta) else [];
  
    checkPlatform = attrs:
      lib.any (lib.meta.platformMatch hostPlatform) attrs.meta.platforms;
  
    # Check if a derivation is valid, that is whether it passes checks for
    # e.g brokenness or license.
  
negative.code:     isFcitxEngine = bool;
      isIbusEngine = bool;
      isGutenprint = bool;
      badPlatforms = platforms;
    };
  
    checkMetaAttr = k: v:
  