I can get it to compile on Windows under C::B and TDM's latest MinGW compiler (stable, from the 4.4.x line), getting results much like Kildor's, although the last commit (according to the log) was from 25th of April.
From BTAxis's comment and looking at the IRC logs, I'm guessing the idea is to keep both the savegame break and trunk branches mostly in sync, so both are up to date but the savegame break branch has it's own unique changes.
I'm also guessing, from these sources, that right now it isn't working too well with the SVN system.
I'm willing to upload an installer for the savegame branch if it can be made up-to-date like the trunk, but as for solving the SVN issue I'm afraid I wouldn't do any better than those who are already working on the problem.