recursion limit checker

gistfile1.c

# 2.7

if (tstate->recursion_depth > recursion_limit) {
        --tstate->recursion_depth;
        PyErr_Format(PyExc_RuntimeError,
                     "maximum recursion depth exceeded%s",
                     where);
        return -1;
        
# 3.4
if (tstate->recursion_depth > recursion_limit) {
        --tstate->recursion_depth;
        tstate->overflowed = 1;
        PyErr_Format(PyExc_RuntimeError,
                     "maximum recursion depth exceeded%s",
                     where);
        return -1;