yum install centos-release-scl -y

替换文件 /etc/yum.repos.d/CentOS-SCLo-scl.repo
[centos-sclo-sclo]
name=CentOS-7 - SCLo sclo
baseurl=https://mirrors.aliyun.com/centos/7/sclo/x86_64/sclo/
gpgcheck=0
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-SIG-SCLo

替换文件 /etc/yum.repos.d/CentOS-SCLo-scl-rh.repo
[centos-sclo-rh]
name=CentOS-7 - SCLo rh
baseurl=https://mirrors.aliyun.com/centos/7/sclo/x86_64/rh/
gpgcheck=0
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-SIG-SCLo

生效
yum clean && yum makecach

安装gcc
yum install devtoolset-8 -y

mv /usr/bin/gcc /usr/bin/gcc-4.8.5
ln -s /opt/rh/devtoolset-8/root/bin/gcc /usr/bin/gcc
ln -s /opt/rh/devtoolset-8/root/bin/g++ /usr/bin/g++