You can download the source code packet hfst-3.x.x.tar.gz from Sourceforge download page. (NOTE: we have officially moved to Github, but for the time being the latest release is still available on Sourceforge.) Extract all files with the command

tar -xzvf hfst-3.x.x.tar.gz

  move to directory hfst-3.x.x and run the commands

autoreconf -i && ./configure && make && make install

  The command 'make' will compile all the API and command line tools and 'install'
  will install them to /usr/local. If you would rather install in eg. your home directory, 
  you can tell ./configure:

./configure --prefix=${HOME}