First step: Dependency Installation
You need to install these things:
subversion scons libxml2-dev libglib2.0-dev libgtk2.0-dev libgtkglext1-dev libmhash-dev gcc g++
For Debian Based systems:
sudo apt-get install subversion scons libxml2-dev libglib2.0-dev libgtk2.0-dev libgtkglext1-dev libmhash-dev gcc g++
For systems using yum:
sudo yum install subversion scons libxml2-dev libglib2.0-dev libgtk2.0-dev libgtkglext1-dev libmhash-dev gcc g++
Second Step: Getting the source
Getting GTKRadiant
This is just checking out the latest version of GTKRadiant 1.6 (codenamed zeroradiant). It will give you a prompt saying an invalid SSL certificate. Just enter "a" and then hit <ENTER>.
svn checkout https://zerowing.idsoftware.com/svn/radiant/GtkRadiant/trunk ./ZeroRadiant-src
Getting a few game packs
This is just telling scons to run the script for setup. The script here is to download some more game packs via subversion.
scons target=setup
Third Step: Compiling
Just run this and scons will automatically do everything for you.
scons target=radiant,q3map2 config=debug
Fourth Step: Installation
This is OPTIONAL! Right now all of the files are in /home/username/ZeroRadiant-src/install. That is kind of inconvenient, so if you run this:
mv ~/ZeroRadiant-src/install/ ~/ZeroRadiant
Or if you want it to be available for all users:
sudo mv ~/ZeroRadiant-src/install/ /opt/ZeroRadiant
sudo chmod a+rx /opt/ZeroRadiant