ref: dffca6aecae11acffcd33a8cf5687fa9e9a7c1db
dir: /sys/src/ape/lib/v/error.c/
#define _POSIX_SOURCE
#define _RESEARCH_SOURCE
#include <error.h>
#include <stdio.h>
#include <libv.h>
char *_progname;
void
_perror(char *s)
{
fprintf(stderr, "%s: ", _progname);
perror(s);
}