I guess it's your Flex that makes compilation fail.
The latest sources in SVN pass an int variable as second argument to ReadLexBuff(), while your log complains about an yy_size_t (a.k.a. long unsigned int) type. Therefore I guess Scanner.cpp gets regenerated on your system before compilation.
I'd say you should try checking out a clean source tree (or discard all of your modifications to Scanner.{cpp,h}), then do $ touch src/Scanner.{cpp,h}
to make their timestamp newer than Scanner.l, then try compiling again. If it still fails, please check that Scanner.cpp isn't modified.