centos7 使用SCL（SoftwareCollection

$ sudo yum install centos-release-scl
$ sudo yum install scl-utils

$ # clang && llvm
$ sudo yum install install llvm-toolset-7

$ scl --list
devtoolset-7
llvm-toolset-7

$ scl enable llvm-toolset-7 bash

$ # bashrc
$ # source /opt/rh/llvm-toolset-7/enable 

$ lldb -version
lldb version 5.0.1

$ clang --version                   
clang version 5.0.1 (tags/RELEASE_501/final)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /opt/rh/llvm-toolset-7/root/usr/bin