heroku拒绝带有M2Crypto错误的Django应用推送

Question

Heroku拒绝了Django版本为3.6.2的Django应用推送，但出现以下错误：

remote:            SWIG/_m2crypto_wrap.c:31145:5:
remote:                 (PyObject*) 0,                            /* ht_name */
remote:                 {
remote:            SWIG/_m2crypto_wrap.c:31147:1:
remote:             };
remote:             }
remote:            error: command 'gcc' failed with exit status 1
remote:            
remote:            ----------------------------------------
remote:        Command "/app/.heroku/python/bin/python -u -c "import setuptools, tokenize;__file__='/tmp/pip-build-pbjs22ys/M2Crypto/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" install --record /tmp/pip-yovrfdk2-record/install-record.txt --single-version-externally-managed --compile" failed with error code 1 in /tmp/pip-build-pbjs22ys/M2Crypto/
remote:  !     Push rejected, failed to compile Python app.
remote: 
remote:  !     Push failed

Django-1.9.4 python-3.6.2 M2Crypto-0.31.0

整个安装程序在本地运行，不知道为什么在heroku push上失败。我已经使用python-3.6.2创建了runtime.txt