solaris: fix compile error on ctime_r()

On Solaris, it takes a 3rd length argument.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/stat.c b/stat.c
index 2665952..d041ef3 100644
--- a/stat.c
+++ b/stat.c
@@ -534,7 +534,7 @@
 		return;
 
 	time(&time_p);
-	ctime_r((const time_t *) &time_p, time_buf);
+	os_ctime_r((const time_t *) &time_p, time_buf, sizeof(time_buf));
 
 	if (!ts->error) {
 		log_info("%s: (groupid=%d, jobs=%d): err=%2d: pid=%d: %s",