What, is it beyond mere mortals' comprehension or something?

What I need to know basically is:
Where to get all the files together (I assume you run that "INSTALL" exe, but you never know...)
Which one is the file with the variable
How to compile
EDIT: the whole source code is on freespace.cpp. I changed the clipping plane distance from 30000 to 400000. Now I've got to find some compiler program.
EDIT2: This file is too small to be a whole source code. Jesus Christ, the source code files are all over the place. Will I have to go through every directory and download everything?!