ref: 2bb0f44eba0775af5e7ce1a73d15a7abf958c13f
dir: /sys/src/libc/port/perror.c/
#include <u.h>
#include <libc.h>
void
perror(char *s)
{
char buf[ERRMAX];
buf[0] = '\0';
errstr(buf, sizeof buf);
if(s && *s)
fprint(2, "%s: %s\n", s, buf);
else
fprint(2, "%s\n", buf);
}