title: Mix hangs on deps.compile while compiling riak_core project
body: <p>I am trying to compile <a href="https://github.com/kanatohodets/elixir_riak_core_ping" rel="nofollow noreferrer">https://github.com/kanatohodets/elixir_riak_core_ping</a>. I have erlang 18 installed and elixir version is 1.3.</p>
  
  <p>compilation hangs at below line and does not move ahead:</p>
  
  <pre><code>Downloaded package, caching at /Users/navinnegi/.cache/rebar3/hex/default/packages/pc-1.4.0.tar
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/HuGL3.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/HuGL3.png" alt="enter image description here"></a></p>
  
  <p>if I stop and try to run deps.compile again, it stops at line </p>
  
  <pre><code>Compiling parse_trans
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/KDMAg.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/KDMAg.png" alt="enter image description here"></a></p>
  
  <p>However if I delete rebar3 folder located at User/username/.cache, and run deps.compile. compilation is stuck on below line again </p>
  
  <p>Downloaded package, caching at /Users/navinnegi/.cache/rebar3/hex/default/packages/pc-1.4.0.tar</p>