Crashes ain't good ;)

I suggest that you chance only a small portion of files at a time, then
make && ./python Lib/test/regrtest.py. Start with the Parser, then move
over to AST and the rest of Python/.

You may have to remove all pyc and pyo files if you change code related
to the Parser, AST and byte code marshaling. I'm not sure if it's
required but it's worth a shot. Bytecode mismatches can lead to strange
errors.