wget -c https://ftp.gnu.org/gnu/gcc/gcc-7.1.0/gcc-7.1.0.tar.bz2
tar -xjf gcc-7.1.0.tar.bz2
cd gcc-7.1.0
mkdir -p build
cd build
../configure --prefix="/usr" --enable-languages="c,c++,fortran,lto,objc,go" --disable-multilib
make # doesn't mind -j#
make install