title: Can no longer import xgboost
body: <p>I have installed Anaconda 3 and lots of packages, including <code>xgboost</code> few months ago and it worked well. But now <code>xgboost</code> stopped working: import fails with</p>
  
  <blockquote>
    <p>OSError:
    /home/user/anaconda3/lib/python3.5/site-packages/scipy/sparse/../../../../libstdc++.so.6:
    version `GLIBCXX_3.4.22' not found (required by
    /home/user/anaconda3/lib/python3.5/site-packages/xgboost/./lib/libxgboost.so)</p>
  </blockquote>
  
  <p>I do see <code>libstdc++.so.6</code> in my <code>lib</code> dir. What might have gone wrong?</p>