报错: No module named '_ctypes'
若在安装前移除了/usr/bin下python的文件链接依赖，此时yum无法正常使用，需要自己下载相关软件包安装，为节省读者时间，放上链接
#wget http://mirror.centos.org/centos/7/os/x86_64/Packages/libffi-devel-3.0.13-18.el7.x86_64.rpm
#rpm -ivh libffi-devel-3.0.13-18.el7.x86_64.rpm
或者 rpm -ivh http://mirror.centos.org/centos/7/os/x86_64/Packages/libffi-devel-3.0.13-18.el7.x86_64.rpm
安装rpm文件报错 : error: Failed dependencies:
添加安装时添加两个参数 : rpm -ivh libffi-devel-3.0.13-18.el7.x86_64.rpm --nodeps --force
然后make clean 重新make