File _constraints of Package libarchive

<constraints>
  <overwrite>
    <conditions>
      <arch>ppc64</arch>
      <arch>ppc64le</arch>
    </conditions>
    <hardware>
      <physicalmemory>
        <size unit="M">4096</size>
      </physicalmemory>
    </hardware>
  </overwrite>
</constraints>