服务器系统版本如下：

原装的gcc版本为4.4，已安装gcc4.8.2，现升级为gcc5.4.0

安装前请清空所有自定义的环境变量，否则会出现错误，类似于

In file included from /home/sczhuhd/install_dir/gcc-5.4.0/gcc/system.h:1104:0,

                 from /home/sczhuhd/install_dir/gcc-5.4.0/gcc/c-family/c-common.c:23:

/home/sczhuhd/install_dir/gcc-5.4.0/gcc/hwint.h:74:9: error: 'HOST_WIDE_INT' does not name a type

 typedef HOST_WIDE_INT __gcc_host_wide_int__;

         ^

/home/sczhuhd/install_dir/gcc-5.4.0/gcc/hwint.h:157:33: error: expected ',' or '...' before 'x'

 clz_hwi (unsigned HOST_WIDE_INT x)

清空环境变量之后，首先下载gcc源码

wget ftp://ftp.mirrorservice.org/sites/sourceware.org/pub/gcc/releases/gcc-5.4.0/gcc-5.4.0.tar.gz

tar zxf gcc-5.4.0.tar.gz

cd gcc-5.4.0

#下载依赖库

./contrib/download_prerequisites

cd ..

mkdir gcc_make

cd gcc_make

../gcc-5.4.0/configure --disable-multilib --enable-languages=c,c++ --prefix=/home/sczhuhd/software/

make -j24

make install