To compile from sources you'll need:

a C/C++ compiler (gcc for most of targets, on Win32 visual C++ may work).

Cmake 2.6 or better.

SDL2 library for developpers.

The Zlib library for developpers.

A subversion (SVN) client.

Detailed procedure for linux ubuntu 12.04 and above:

(tested with ubuntu 12.04 amd64 freshly installed from iso image with virtualbox)

Open a terminal window:

_ install C++ compiler, cmake, subversion and library

sudo apt-get install g++
sudo apt-get install cmake
sudo apt-get install subversion
sudo apt-get install zlib1g-dev
sudo apt-get install libpng-dev

(please note that on a new ubuntu installed machine, apt-get may be locked until all other package managers are running... wait a bit...)

create a build dir
mkdir previous

For ubuntu 14.04 and above (SDL2 is already a package):
sudo apt-get install libsdl2-dev

Otherwise (need to compile SDL2 from sources):
SDL2 version 2.0.4 is not part of ubuntu until 14.04, you need to compile from sources and at least with video support.

cd previous

wget http://www.libsdl.org/release/SDL2-2.0.4.tar.gz
tar xzf SDL2-2.0.4.tar.gz

Install some sdl dependencies (this is a single line):
sudo apt-get install libudev-dev libts-dev libgl1-mesa-dev libglu1-mesa-dev libasound2-dev libpulse-dev libopenal-dev libaudiofile-dev libdbus-1-dev libdirectfb-dev


cd SDL2.0.4
./configure

At the end of configure check that audio and video driver are present
audio : one or many from (oss,alsa,pulse)
video : x11 opengl

make
sudo make install
cd ..

SDL2 2.0.4 is now installed on your system


get latest source code from sourceforge (branch branch_realtime) (this is a single line):
svn checkout svn://svn.code.sf.net/p/previous/code/branches/branch_realtime previous-code

cd previous-code
./configure
make

Run the program
cd src
./Previous