小心这个错误
c++: 编译器内部错误：已杀死(程序 cc1plus) ＃ 内存不足，可解决的
复制如下命令：
yum install cmake python-devel numpy gcc gcc-c++ gtk2-devel libdc1394-devel libv4l-devel ffmpeg-devel gstreamer-plugins-base-devel libpng-devel libjpeg-turbo-devel jasper-devel openexr-devel libtiff-devel libwebp-devel opencv opencv-python opencv-devel
然后：
pip install dlib
ps：ffmpeg-devel 可能安装失败
1.可能不需要这步
配置Yum源为阿里源
备份：
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
配置：
cd /etc/yum.repos.d/
sudo wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
sudo yum makecache
删除/etc/yum.repos.d下的devtools-2.repo就恢复了
sudo mv devtools-2.repo devtools-2.repo.bat
2.
yum -y install epel-release
# Install the nux repository
rpm -Uvh http://li.nux.ro/download/nux/dextop/el7/x86_64/nux-dextop-release-0-5.el7.nux.noarch.rpm
# Install ffmpeg and ffmpeg -devel packages
yum install ffmpeg ffmpeg-devel -y