在执行“python setup.py build_amalgamation”命令时，报错“Fatal error: OpenSSL could not be detected!“

我在安装pysqlcipher3，（参考文章：https://zhuanlan.zhihu.com/p/164917107

在执行“python setup.py build_amalgamation”命令时，报错“Fatal error: OpenSSL could not be detected!”。但是当我输入openssl是可以进到OpenSSL>，环境变量也已经添加了。请问这是什么问题？

PS C:\Users\bl-37\Desktop\pysqlcipher3> openssl
OpenSSL>
PS C:\Users\bl-37\Desktop\pysqlcipher3> python setup.py build_amalgamation
running build_amalgamation
Builds a C extension using a sqlcipher amalgamation
Fatal error: OpenSSL could not be detected!
PS C:\Users\bl-37\Desktop\pysqlcipher3>