Missing instruction how to install clipnotify

[AntonSamokat]

Please add it in readme

[KenH2000]

I had to do some research and trial and error to figure out how to include the libraries to get the source to compile without errors. This command finally worked:

gcc clipnotify.c -o clipnotify -lX11 -lXfixes

Then I copied the created binary to /home/$USER/.local/bin/

If you get an error, you may need to install libxfixes3 and or libxfixes-dev for the Xfixes library. You can check if they are already installed with this command:

apt-cache policy libxfixes*