gettime: if setaffinity fails, print the errno error

Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/gettime.c b/gettime.c
index 72968c5..f40abc7 100644
--- a/gettime.c
+++ b/gettime.c
@@ -481,7 +481,9 @@
 	fio_cpu_set(&cpu_mask, t->cpu);
 
 	if (fio_setaffinity(gettid(), cpu_mask) == -1) {
-		log_err("clock setaffinity failed\n");
+		int __err = errno;
+
+		log_err("clock setaffinity failed: %s\n", strerror(__err));
 		return (void *) 1;
 	}