sudo apt-get install build-essential  libgmp-dev libmpfr-dev libmpc-dev
wget http://mirror.linux-ia64.org/gnu/gcc/releases/gcc-8.2.0/gcc-8.2.0.tar.xz
tar -Jxvf gcc-8.2.0.tar.xz
cd gcc-8.2.0
## 下面这步特别重要，如果不unset这些环境变量，编译会失败
unset LIBRARY_PATH CPATH C_INCLUDE_PATH PKG_CONFIG_PATH CPLUS_INCLUDE_PATH INCLUDE
./contrib/download_prerequisites
cd .. && mkdir temp_gcc82 && cd temp_gcc82
../gcc-8.2.0/configure --prefix=/usr/local/gcc-8.2 --enable-threads=posix --disable-checking --disable-multilib
make
sudo make install
## 根据需求设置环境变量
export PATH=/usr/local/gcc-8.2/bin:$PATH