GSB uses go-oo (go-oo.org) as the basis for building Openoffice.org. go-oo 
supplies milestone source balls in additional to supplementary software used by 
openoffice (like mdbtools).  The GSB download scripts will keep the source in the 
svn tree, and copy them over the build tree later (instead of running the 
./download script which comes with ooo-build)