http://askubuntu.com/questions/428873/errors-running-make-on-wifi-kernel-module

sudo apt-get install linux-headers-generic build-essential git
git clone http://github.com/lwfinger/rtl8723be
cd rtl8723be
make clean
git checkout 604aa9058fb9e5bb1cf571c99989d081f8fc8b9
make
sudo make install
sudo ...