Add functions PyUnicode_Append() and PyUnicode_AppendAndDel() that mirror PyString_Concat() and PyString_ConcatAndDel() (the name PyUnicode_Concat() was already taken). Change PyObject_Repr() to always return a unicode object. Update all repr implementations to return unicode objects. Add a function PyObject_ReprStr8() that calls PyObject_Repr() and converts the result to an 8bit string. Use PyObject_ReprStr8() where using PyObject_Repr() can't be done straightforward.

/* PD implementation of strerror() for systems that don't have it.
   Author: Guido van Rossum, CWI Amsterdam, Oct. 1990, <guido@cwi.nl>. */

#include <stdio.h>
#include "Python.h"

extern int sys_nerr;
extern char *sys_errlist[];

char *
strerror(int err)
{
	static char buf[20];
	if (err >= 0 && err < sys_nerr)
		return sys_errlist[err];
	PyOS_snprintf(buf, sizeof(buf), "Unknown errno %d", err);
	return buf;
}