CVE-2013-4237, BZ #14699: Buffer overflow in readdir_r

CVE-2013-4237, BZ #14699: Buffer overflow in readdir_r

	* sysdeps/posix/dirstream.h (struct __dirstream): Add errcode
	member.
	* sysdeps/posix/opendir.c (__alloc_dir): Initialize errcode
	member.
	* sysdeps/posix/rewinddir.c (rewinddir): Reset errcode member.
	* sysdeps/posix/readdir_r.c (__READDIR_R): Enforce NAME_MAX limit.
	Return delayed error code.  Remove GETDENTS_64BIT_ALIGNED
	conditional.
	* sysdeps/unix/sysv/linux/wordsize-64/readdir_r.c: Do not define
	GETDENTS_64BIT_ALIGNED.
	* sysdeps/unix/sysv/linux/i386/readdir64_r.c: Likewise.
	* manual/filesys.texi (Reading/Closing Directory): Document
	ENAMETOOLONG return value of readdir_r.  Recommend readdir more
	strongly.
	* manual/conf.texi (Limits for Files): Add portability note to
	NAME_MAX, PATH_MAX.
	(Pathconf): Add portability note for _PC_NAME_MAX, _PC_PATH_MAX.