anchor.diff:      // Prepare results.
       //
       String sdkPath = args.length > 2 ? args[2] : null;
  -    _Output output = _buildMultipleOutputs(sdkPath);
  +    _Output output = _buildMultipleOutputs(sdkPath, includeSpec);
       if (output == null) {
         exitCode = 1;
         return;
  
positive.code:     //
      // Prepare results.
      //
      _Output output = _buildMultipleOutputs(sdkPath);
      if (output == null) {
        exitCode = 1;
        return;
  
negative.code:   //
    // Build spec and strong outputs.
    //
    _BuilderOutput spec =
        includeSpec ? new _Builder(sdkPath, false).build() : null;
    _BuilderOutput strong = new _Builder(sdkPath, true).build();
    return new _Output(spec, strong);
  }
  