ref: 1bd4c243ada35e70ff3c92e4019fb6adcc9b4bdc
dir: /sys/src/libc/9sys/rerrstr.c/
#include <u.h>
#include <libc.h>
void
rerrstr(char *buf, uint nbuf)
{
char tmp[ERRMAX];
tmp[0] = 0;
errstr(tmp, sizeof tmp);
utfecpy(buf, buf+nbuf, tmp);
errstr(tmp, sizeof tmp);
}