add user-modifiable recursion_limit

ceval.c:
    define recurion_limit (static), default value is 2500
    define Py_GetRecursionLimit and Py_SetRecursionLimit
    raise RuntimeError if limit is exceeded
PC/config.h:
    remove plat-specific definition
sysmodule.c:
    add sys.(get|set)recursionlimit
4 files changed