Create a folder somewhere, whatever you prefer, but I would recommend to keep all the code in the same place. For example create one in you home directory
mkdir -p ~/code/x2go && cd ~/code/x2go
You should now have cloned all repositories actually shown at the gitweb here.
Install the following packages for development (Debian/Ubuntu based distro):
Note: Some packages are optional.
sudo apt-get install build-essential qt4-default qt4-designer qtcreator qtcreator-doc \ qt4-demos qt4-doc qt4-dev-tools libqt4-dev git \ libldap2-dev libssh-dev libxpm-dev libcups2-dev \ debhelper doxygen man2html-base xutils-dev libpixman-1-dev\ devscripts quilt libxcomposite-dev libxrandr-dev\ libxtst-dev libxinerama-dev libxrender-dev pkg-config expat\ libxmltok1-dev libxml2-dev libxfont-dev
All up-to-date dependencies you can get with dpkg-checkbuilddeps command.
Before you build, consider this: when you're on the master branch, you're on the bleeding edge. This could contain any sort of errors or experimental code. Have a look at the available tags:
Also, you might want to have in mind, that the actual build is based on the branch build-main. Have a look at what's there with
git branch <TAB><TAB>
Change to the branch or tag of project you want to build and build the project with:
debuild -us -uc