code: public void setUndefine(final CUtil.StringArrayBuilder undefList) throws BuildException {
      if (isReference()) {
        throw tooManyAttributes();
      }
      addDefines(undefList.getValue(), false);
    }
docs: A comma-separated list of preprocessor macros to undefine.
  
  @param undefList
  comma-separated list of preprocessor macros
  @throws BuildException
  throw if defineset is a reference