COCO APIのインストールでerror: no such file or directory: ‘pycocotools/_mask.c’

Tensorflow Object Detection APIを導入するにあたり、COCO API installationが必要

Models and examples built with TensorFlow. Contribute to tensorflow/models development by creating an account on GitHub.

git clone https://github.com/cocodataset/cocoapi.git
cd cocoapi/PythonAPI
make

が、エラー発生。

clang: error: no such file or directory: 'pycocotools/_mask.c'
clang: error: no input files
error: command 'clang' failed with exit status 1
make: *** [all] Error 1

_mask.cがないと怒られる。

pip install cython

してから再度makeするとビルドできた。

参考

pycocotools/_mask.c:547:21: fatal error: maskApi.h: No such file or directory · Issue #141 · cocodataset/cocoapi

I am sorry for asking this stupid question, I got this error, and I don't know why python setup.py build_ext --inplace running build_ext building 'pycocotools._...