Change PyErr_Format() to generate a unicode string (by using PyUnicode_FromFormatV() instead of PyString_FromFormatV()). Change calls to PyErr_Format() to benefit from the new format specifiers: Using %S, object instead of %s, PyString_AS_STRING(object) with will work with unicode objects too.

#include "Python.h"

#ifndef PLATFORM
#define PLATFORM "unknown"
#endif

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