错误种类：
from /usr/local/lib/python2.7/dist-packages/tensorflow/include/tensorflow/core/framework/op.h:32
fatal error: nsync_time.h: No such file or directory
解决方案：
copying nsync*.h from dist-packages/external/nsync/public (or https://github.com/google/nsync/tree/master/public) to /usr/include also does the trick without modifying tensorflow files.