Fix a crasher where Python code managed to infinitely recurse in C code without ever going back out to Python code in PyObject_Call(). Required introducing a static RuntimeError instance so that normalizing an exception there is no reliance on a recursive call that would put the exception system over the recursion check itself.

#include "Python.h"

#ifndef PLATFORM
#define PLATFORM "unknown"
#endif

const char *
Py_GetPlatform(void)
{
	return PLATFORM;
}