[PATCH] Add missing inclusion of libc-internal.h.

[Stefan Liebler]

Committed.
See discussion on thread "Deprecate readdir_r, readdir64_r [BZ #19056]":
https://www.sourceware.org/ml/libc-alpha/2016-02/msg00678.html

On 02/22/2016 10:24 AM, Stefan Liebler wrote:
> Hi,
>
> The build of posix/tst-dir.c fails due to undefined DIAG_* macros.
> The usage of these macros were introduced in recent commit
> 7584a3f96de88d5eefe5d6c634515278cbfbf052
> "Deprecate readdir_r, readdir64_r [BZ #19056]".
> This patch adds the missing header libc-internal.h.
>
> Bye
> Stefan
>
> ChangeLog:
>
>      * posix/tst-dir.c: Include libc-internal.h.