我要在python virtualenv环境中安装Mac。每当我安装需求包命令“ pip install -r requirements.txt”时，我都会收到此消息。
pip install -r requirements.txt ----------------------------------------
Failed building wheel for xmlsec
Running setup.py clean for xmlsec
Failed to build xmlsec
Installing collected packages: xmlsec, python3-saml, raven, scrypt, social-auth-app-django, social-auth-steemconnect, w3lib, voluptuous, ujson, toolz, steem
Running setup.py install for xmlsec ... error
Complete output from command
/Users/leebom/Documents/workspace/lineup/backend/venv/bin/python3.6 -u -c "import setuptools, tokenize;__file__='/private/var/folders/p5/385n2cr95sq16x17334vsbnr0000gq/T/pip-install-xn4yfy51/xmlsec/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" install --record /private/var/folders/p5/385n2cr95sq16x17334vsbnr0000gq/T/pip-record-kpdy8vo4/install-record.txt --single-version-externally-managed --compile --install-headers /Users/leebom/Documents/workspace/lineup/backend/venv/bin/../include/site/python3.6/xmlsec:
running install
running build
running build_ext
************************************************************************
Could not find xmlsec1 config. …