-Wunused-local-typedefs is a new warning flag of gcc-4.7, and it will enabled
by -Wall since gcc-4.8 (not yet released).
The fix is a big set of removals of unused typedefs (or comments, or moves,
depending on the context).
Freie Universitaet Berlin (Germany), Martin-Luther-University Halle-Wittenberg
(Germany) and RISC Linz (Austria) as they transfer the copyright to other
sites.