外部环境：ubuntu16.04, 64bits, 全局环境python2.7

在虚拟环境(python3.5)中执行 pip install wordcloud 时安装失败，报错：

error: command 'x86_64-linux-gnu-gcc' failed with exit status 

  ----------------------------------------

  Failed building wheel for wordcloud

  Running setup.py clean for wordcloud

Failed to build wordcloud

解决方案：在外部环境执行 sudo apt-get install python3-dev ，再在虚拟环境中重新 pip install wordcloud 即可。

参考：

http://www.cnblogs.com/canitang/p/7994184.html