How to install several Emacs versions on the same system?

[Marcin Borkowski]

Hi all,

I'm on GNU Emacs 25.0.50.1, but I'd like to have an older Emacs
installed, too.  What is the fastest way to achive that?  (I would
prefer to compile from source - I have the Git repository anyway, though
only shallow clone, but I can clone the whole thing, too.)

TIA,

-- 
Marcin Borkowski
http://octd.wmi.amu.edu.pl/en/Marcin_Borkowski
Faculty of Mathematics and Computer Science
Adam Mickiewicz University