docs: def append_var(var, value):
      '''
      Add to or create a new variable in the make.conf
  
      Return a dict containing the new value for variable::
  
          {'<variable>': {'old': '<old-value>',
                          'new': '<new-value>'}}
  
      CLI Example:
  
      .. code-block:: bash
  
          salt '*' makeconf.append_var 'LINGUAS' 'en'
      '''
      makeconf = _get_makeconf()
  
      old_value = get_var(var)
  
      # If var already in file, add to its value
      if old_value is not None:
          appended_value = '{0} {1}'.format(old_value, value)
          __salt__['file.sed'](makeconf, '^{0}=.*'.format(var),
                               '{0}="{1}"'.format(var, appended_value))
      else:
          _add_var(var, value)
  
      new_value = get_var(var)
      return {var: {'old': old_value, 'new': new_value}}