I make no guarantees on the 0.3 branch right now.
Also, the linux build is a bit odd if you ask me, but it's the way it was set up before I started working on GAE, it creates links to other directories when it compiles and runs. Object files (.o) are compiled C or C++ files and you shouldn't need to open or edit them unless you are doing some serious debugging or performance analysis (examining generated instructions, etc.). Also, note that the autogen.sh script creates the directory under /tmp/gae/build and links "build" to that directory. This is done because /tmp is usually a tempfs system and compiling to tempfs is usually *much* faster. But if you do not have very much memory (1GB or less), I would suggest removing the "build" link and creating a subdirectory instead to save memory when compiling, otherwise, the kernel will be forced to page out your compiled object files negating the benefit of using tempfs.
cd mk/linux
rm build
rm -rf /tmp/gae/build
mkdir build