系统：macOS Sierra

pip install MySQL-python,pip install psycopg2均报以下错误：

ld: library not found for -lssl clang: error: linker command failed with exit code 1 (use -v to see invocation) error: command 'cc' failed with exit status 1

报错显示没有找到lssl这个库，我用Google搜索how to install lssl on mac还是没有找到如何安装呀，请问这个问题我该怎么解决？谢谢