title: Execution import error after success pip install compilation
body: <h2>My trouble</h2>
  
  <p>On clean Ubuntu 16.04 environment, I want to install and use Crossbar.io.</p>
  
  <p>I have already <strong>installed pypy from ppa, virtualenv</strong> and activate a new pypy virtualenv.</p>
  
  <p>I had some error while installing crossbar via command <code>pip install crossbar</code> but solved using this build command:</p>
  
  <pre><code>pip install --no-cache-dir --global-option=build_ext --global-option="-I/usr/include/python2.7" crossbar
  </code></pre>
  
  <p>Now when launching crossbar with <code>crossbar version</code> I got the following error:</p>
  
  <pre><code>Traceback (most recent call last):
    File "/home/visiboost/gmm_pypy_env2/bin/crossbar", line 11, in &lt;module&gt;
      load_entry_point('crossbar==17.6.1.post3', 'console_scripts', 'crossbar')()
    File "/home/visiboost/gmm_pypy_env2/site-packages/pkg_resources/__init__.py", line 542, in load_entry_point
      return get_distribution(dist).load_entry_point(group, name)
    File "/home/visiboost/gmm_pypy_env2/site-packages/pkg_resources/__init__.py", line 2569, in load_entry_point
      return ep.load()
    File "/home/visiboost/gmm_pypy_env2/site-packages/pkg_resources/__init__.py", line 2229, in load
      return self.resolve()
    File "/home/visiboost/gmm_pypy_env2/site-packages/pkg_resources/__init__.py", line 2235, in resolve
      module = __import__(self.module_name, fromlist=['__name__'], level=0)
    File "/home/visiboost/gmm_pypy_env2/site-packages/crossbar/controller/cli.py", line 62, in &lt;module&gt;
      from crossbar.controller.node import _read_release_pubkey, _read_node_pubkey
    File "/home/visiboost/gmm_pypy_env2/site-packages/crossbar/controller/node.py", line 44, in &lt;module&gt;
      from nacl.signing import SigningKey
    File "/home/visiboost/gmm_pypy_env2/site-packages/nacl/signing.py", line 19, in &lt;module&gt;
      import nacl.bindings
    File "/home/visiboost/gmm_pypy_env2/site-packages/nacl/bindings/__init__.py", line 17, in &lt;module&gt;
      from nacl.bindings.crypto_box import (
    File "/home/visiboost/gmm_pypy_env2/site-packages/nacl/bindings/crypto_box.py", line 18, in &lt;module&gt;
      from nacl._sodium import ffi, lib
  ImportError: unable to load extension module '/home/visiboost/gmm_pypy_env2/site-packages/nacl/_sodium.pypy-41-x86_64-linux-gnu.so': /home/visiboost/gmm_pypy_env2/site-packages/nacl/_sodium.pypy-41-x86_64-linux-gnu.so: undefined symbol: _Py_NoneStruct
  </code></pre>
  
  <p>I try adding path by settings environment variable before launching but no success:</p>
  
  <pre><code>export LD_LIBRARY_PATH=/usr/lib/python2.7/config-x86_64-linux-gnu/:/usr/lib/x86_64-linux-gnu/
  </code></pre>
  
  <h2>My environment</h2>
  
  <ul>
  <li>Ubuntu 16.04 / 4.4.0-87-generic</li>
  <li>Python 2.7.13 (5.8.0+dfsg-2~ppa2~ubuntu16.04, Jun 17 2017, 18:50:19)</li>
  <li>[PyPy 5.8.0 with GCC 5.4.0 20160609]</li>
  <li>pip 9.0.1 from /home/visiboost/gmm_pypy_env2/site-packages (python 2.7)</li>
  </ul>
  
  <p>Results of ldd on failing library:</p>
  
  <pre><code>ldd -r /home/visiboost/gmm_pypy_env2/site-packages/nacl/_sodium.pypy-41-x86_64-linux-gnu.so
      linux-vdso.so.1 =&gt;  (0x00007fff31ddd000)
      libsodium.so.18 =&gt; /usr/lib/x86_64-linux-gnu/libsodium.so.18 (0x00007fe336153000)
      libpthread.so.0 =&gt; /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007fe335f0c000)
      libc.so.6 =&gt; /lib/x86_64-linux-gnu/libc.so.6 (0x00007fe335b41000)
      /lib64/ld-linux-x86-64.so.2 (0x0000564659a68000)
  undefined symbol: _Py_NoneStruct    (/home/visiboost/gmm_pypy_env2/site-packages/nacl/_sodium.pypy-41-x86_64-linux-gnu.so)
  undefined symbol: PyObject_CallMethod   (/home/visiboost/gmm_pypy_env2/site-packages/nacl/_sodium.pypy-41-x86_64-linux-gnu.so)
  undefined symbol: PyEval_RestoreThread  (/home/visiboost/gmm_pypy_env2/site-packages/nacl/_sodium.pypy-41-x86_64-linux-gnu.so)
  undefined symbol: PyLong_FromVoidPtr    (/home/visiboost/gmm_pypy_env2/site-packages/nacl/_sodium.pypy-41-x86_64-linux-gnu.so)
  undefined symbol: PyArg_UnpackTuple (/home/visiboost/gmm_pypy_env2/site-packages/nacl/_sodium.pypy-41-x86_64-linux-gnu.so)
  undefined symbol: PyErr_Occurred    (/home/visiboost/gmm_pypy_env2/site-packages/nacl/_sodium.pypy-41-x86_64-linux-gnu.so)
  undefined symbol: PyImport_ImportModule (/home/visiboost/gmm_pypy_env2/site-packages/nacl/_sodium.pypy-41-x86_64-linux-gnu.so)
  undefined symbol: PyLong_FromUnsignedLong   (/home/visiboost/gmm_pypy_env2/site-packages/nacl/_sodium.pypy-41-x86_64-linux-gnu.so)
  undefined symbol: PyInt_FromLong    (/home/visiboost/gmm_pypy_env2/site-packages/nacl/_sodium.pypy-41-x86_64-linux-gnu.so)
  undefined symbol: PyEval_SaveThread (/home/visiboost/gmm_pypy_env2/site-packages/nacl/_sodium.pypy-41-x86_64-linux-gnu.so)
  </code></pre>
  
  <p>Have you any ideas ?</p>