I think there is no real code ownership. I see two ways to ask questions. First use this thread, second post to programmer mailing list.
No ownership... so can everyone mess with everyone's code? Doesn't this lead to conflicts? ("How dare you touch my code!? Why you little...")
No. All code contributed must be under the GPL, or where appropriate (eg, contributions to GG) the LGPL. Therefore, anyone is permitted to touch anyone else's code. We don't really worry here about someone touching a portion someone else wrote - it's all towards the goal of making the game better.
However, if you change something from being good code to bad code, undoubtedly there will be annoyed responses
If coders are not contributing helpfully, then they will have their permissions removed.
As for backtracking, CVS does keep track of all code, so if a rogue coder makes a bungle, it is simple to revert to before they made bad changes.
While writing this from memory, i believe <SDL/SDL.h> is only possible when using precompiled sdl.dll. I for instance rebuild the SDL codebase. So my include path for SDL is somewhat like "../SDL.1.6.7/include" .
Well, a header is a header, I personally put them into my common include dir even when I compile something myself. I think a lot of make install scripts do this too.
I think that we should change references to <SDL/SDL.h> where possible, as this is the standard. I'm not sure that there is a good reason not to.
As a side note - I (we) would also appreciate if you could learn how to write doxygen style comments and do this. The GG sources are written in such a format, so will provide you with an excellent example of how. Not everyone has been, but it would be in our best interests if we could have new coders stick to this habit.