File _service of Package ethereum-cpp

<services>
  <service name="obs_scm">
    <param name="versionprefix">1.3.0~pre</param>
    <param name="url">https://github.com/ethereum/cpp-ethereum.git</param>
    <param name="scm">git</param>
    <param name="submodules">enable</param>
  </service>
  <service name="tar" mode="buildtime"/>
  <service name="recompress" mode="buildtime">
    <param name="compression">xz</param>
    <param name="file">*.tar</param>
  </service>
  <service name="set_version" mode="buildtime">
    <param name="file">ethereum-cpp.spec</param>
  </service>
</services>