参考https://www.cnblogs.com/lazyInsects/p/9778910.html
cd /usr/src
wget https://mirrors.tuna.tsinghua.edu.cn/gnu/gcc/gcc-7.2.0/gcc-7.2.0.tar.xz
ls
tar xvf gcc-7.2.0.tar.xz
mkdir gcc7objdir
yum install gmp-devel -y
yum install mpfr-devel -y
yum install libmpc-devel -y
wget ftp://gcc.gnu.org/pub/gcc/infrastructure/isl-0.15.tar.bz2
yum install bzip2 -y
tar -jxvf isl-0.15.tar.bz2
cd isl-0.15
./configure
make && make install
cd ../gcc7objdir/
../gcc-7.2.0/configure --prefix=/usr/local/gcc7 --enable-checking=release --enable-languages=c,c++,go --disable-multilib
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/lib
make -j4
make installrm -rf /usr/bin/gcc
rm -rf /usr/bin/g++
ln -s /usr/local/gcc7/bin/gcc /usr/bin/gcc
ln -s /usr/local/gcc7/bin/g++ /usr/bin/g++
gcc -v