media thumbnailer: fix compilation with Xcode 4.something
media thumbnailer: fix compilation with Xcode 4.something

CollabraMusic/VLCKit,kamcord/VLCKit,waterskier2007/VLCKit,larrytin/VLCKit,strukturag/VLCKit,kamcord/VLCKit,CollabraMusic/VLCKit,programming086/VLCKit,brion/VLCKit,programming086/VLCKit,kamcord/VLCKit,siuying/VLCKit,siuying/VLCKit,siuying/VLCKit,strukturag/VLCKit,i386/vlckit,hpsoar/VLCKit,simon1984/test,CollabraMusic/VLCKit,larrytin/VLCKit,simon1984/test,waterskier2007/VLCKit,waterskier2007/VLCKit,simon1984/test,hpsoar/VLCKit