CentOS 6.6自带的是Python 2.6.6，而编译llvm需要Python 2.7以上。
checking for python... /usr/bin/pythonchecking for python >= 2.7... not foundconfigure: error: found python 2.6.6 (/usr/bin/python); required >= 2.7
yum中最新的也是Python 2.6.6，只能下载Python 2.7.9的源代码自己编译安装。
操作步骤如下：
1）安装devtoolset
yum groupinstall "Development tools"
2）安装编译Python需要的包包
yum -y install zlib-develyum -y install bzip2-develyum -y install openssl-develyum -y install ncurses-develyum -y install sqlite-devel
3）下载并解压Python 2.7.9的源代码
ftp上传安装包
tar zxvf Python-2.7.9.tar.xzcd Python-2.7.9
4）编译与安装Python 2.7.9
./configure --prefix=/usr/localmake && make altinstall
5）将python命令指向Python 2.7.9
ln -s /usr/local/bin/python2.7 /usr/local/bin/python
6）检查Python版本
shsh-4.1# python -VPython 2.7.9