env | grep '^LIBRARY_PATH='
Apparently, your LIBRARY_PATH ends in a colon:
/usr/lib/x86_64-linux-gnu/:
# -----------------------^
take off the colon in the end
wget [http://mirrors-usa.go-parts.com/gcc/releases/gcc-5.4.0/gcc-5.4.0.tar.bz2](http://mirrors-usa.go-parts.com/gcc/releases/gcc-5.4.0/gcc-5.4.0.tar.bz2)
tar -zxvf gcc-5.4.0.tar.bz2
cd gcc-5.4.0
./contrib/download_prerequisites
mkdir build
cd build
../configure --disable-checking --enable-languages=c,c++ --disable-multilib --prefix=/path/to/install/gcc-5.4 --enable-threads=posix
make -j32 && make install
添加环境便量
CC=install/path + /bin/gcc
or
CXX=install/path + /bin/gcc
