tar xvf gcc-4.7.1.tar.bz2
cd gcc-4.7.1
./contrib/download_prerequisites
mkdir build
cd build
../configure --build=x86_64-linux-gnu --prefix=/usr/gcc_4_7 --enable-checking=release --enable-languages=c,c++ --disable-multilib --program-suffix=-4.7
make
sudo ln -s /usr/lib/x86_64-linux-gnu /usr/lib64
sudo make install