ref: ce5a3ad08abca12b1ed25a4e94f3274833a27fa5
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);
}