Just follow the proedure of http://www.desy.de/~akalay/xilinx_ise_postinstallation.html
cd Xilinx_ISE_DS_Lin_14.7_1015_1/
sudo ./xsetup
sudo vi /etc/profile.d/Xilinx.sh (create Xilinx.sh see original page for contents)
sudo apt-get install fxload libusb-0.1-4 libusb-dev
sudo cp /opt/Xilinx/14.7/ISE_DS/ISE/bin/lin64/xusbdfwu.rules /etc/udev/rules.d/xusbdfwu.rules
sudo sed -i -e 's/TEMPNODE/tempnode/' -e 's/SYSFS/ATTRS/g' -e 's/BUS/SUBSYSTEMS/' /etc/udev/rules.d/xusbdfwu.rules
sudo cp /opt/Xilinx/14.7/ISE_DS/common/bin/lin64/xusb*.hex /usr/share
sudo ln -s /usr/lib/x86_64-linux-gnu/libusb-0.1.so.4 /usr/lib/libusb.so
sudo /etc/init.d/udev restart
sudo sed -i -e 's/#!\/bin\/sh/#!\/bin\/bash/' /opt/Xilinx/14.7/ISE_DS/ISE/bin/lin64/unwrapped/analyzer
sudo apt-get install libstdc++5
sudo apt-get install g++
cd /opt/Xilinx/14.7/ISE_DS/common/lib/lin64
sudo mv libstdc++.so libstdc++.so.bak
sudo mv libstdc++.so.6 libstdc++.so.6.bak
sudo mv libstdc++.so.6.0.8 libstdc++.so.6.0.8.bak
sudo ln -s /usr/lib/gcc/x86_64-linux-gnu/4.7/libstdc++.so libstdc++.so
sudo ln -s libstdc++.so libstdc++.so.6
sudo ln -s libstdc++.so libstdc++.so.6.0.8
sudo ln -s /usr/bin/make /usr/bin/gmake