Ok, I've upped the limit to some very high value and tried to provoke a
stack overflow.
eval("["*x+"]"*x) segfaults on my machine for x somewhere around 20000
(linux, amd64). When setting MAXSTACK to 5000 eval("["*x+"]"*x) works
for x <= 333. So, I guess this should be safe guess (even for the BSDs,
which have a smaller default stack size).

BTW: The hardest part was recognizing that nothing gets rebuilt and that
more then parser.o depended on parser.h. Don't you have some kind of
automatic dependency tracking? Or am I missing some build tools?

Anyway, patch in http://bugs.python.org/issue1881