[libglnx] dirfd: Add missing includes for errno

[Colin Walters <walters src gnome org>]

commit 1468b70dbf19fc48cfbf0b19b7c7ffa9157cfb84
Author: Colin Walters <walters verbum org>
Date:   Thu Jul 20 15:11:32 2017 -0400

    dirfd: Add missing includes for errno
    
    Thought the previous patch would have been obvious enough not
    to compile test but...

 glnx-dirfd.h |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/glnx-dirfd.h b/glnx-dirfd.h
index 4824bc4..8e582fc 100644
--- a/glnx-dirfd.h
+++ b/glnx-dirfd.h
@@ -21,6 +21,8 @@
 #pragma once
 
 #include <glnx-backport-autocleanups.h>
+#include <glnx-macros.h>
+#include <glnx-errors.h>
 #include <limits.h>
 #include <dirent.h>
 #include <sys/stat.h>