when compile /home/wangxiao/NVIDIA-CUDA-7.5 SAMPLES, it warning: gcc version larger than 4.9 not supported, so: old verson of gcc and g++ are needed

1. when compile /home/wangxiao/NVIDIA-CUDA-7.5 SAMPLES, it warning: gcc version larger than 4.9 not supported, so:
old verson of gcc and g++ are needed:

    sudo apt-get install gcc-4.7
    sudo apt-get install g++-4.7    

then, a link needed :

sudo ln -s /usr/bin/gcc-4.7 /usr/local/cuda/bin/gcc
sudo ln -s /usr/bin/g++-4.7 /usr/local/cuda/bin/g++