Function parse_err

ccan/ccan/opt/parse.c:16–22

glibc does this as: /tmp/opt-example: invalid option -- 'x' /tmp/opt-example: unrecognized option '--long' /tmp/opt-example: option '--someflag' doesn't allow an argument /tmp/opt-example: option '--s' is ambiguous /tmp/opt-example: option requires an argument -- 's' */

/tmp/opt-example: option requires an argument -- 's'
*/
static int parse_err(void (*errlog)(const char *fmt, ...),
		     const char *argv0, const char *arg, unsigned len,
		     const char *problem)
{
	errlog("%s: %.*s: %s", argv0, len, arg, problem);
	return -1;
}

static void consume_option(int *argc, char *argv[], unsigned optnum)
{