Easy way:
 $ su
Copy src/wmthrottle somewhere to your path, e.g.
 # cp src/wmthrottle /usr/local/bin/wmthrottle
Make it run as root to be able to use it as a normal user
 # chmod u+s /<path-to>/wmthrottle

"Hard" way:
 $ make
 $ su
 # make install
Make it always run as root to be able to use it as a normal user
 # chmod u+s /usr/local/bin/wmthrottle