rpm包可以从这两个个地方获取：
http://mirrors.163.com/centos/6/os/x86_64/Packages/
Index of /centos/7/os/x86_64/Packages/
mpfr-3.1.1-4.el7.x86_64.rpm
libmpc-1.0.1-3.el7.x86_64.rpm
kernel-headers-3.10.0-123.el7.x86_64.rpm
glibc-headers-2.17-55.el7.x86_64.rpm
glibc-devel-2.17-55.el7.x86_64.rpm
cpp-4.8.2-16.el7.x86_64.rpm
gcc-4.8.2-16.el7.x86_64.rpm
2、将这些包上传到待安装的系统中，按如下顺序执行安装命令：rpm -ivh mpfr-3.1.1-4.el7.x86_64.rpm
rpm -ivh libmpc-1.0.1-3.el7.x86_64.rpm
rpm -ivh kernel-headers-3.10.0-123.el7.x86_64.rpm
rpm -ivh glibc-headers-2.17-55.el7.x86_64.rpm
rpm -ivh glibc-devel-2.17-55.el7.x86_64.rpm
rpm -ivh cpp-4.8.2-16.el7.x86_64.rpm
rpm -ivh gcc-4.8.2-16.el7.x86_64.rpm
也可以使用如下命令统一安装（我本人是使用统一安装成功的）：
rpm -Uvh *.rpm --nodeps --force
3、都安装成功后，验证gcc -v
