Win32 dirent: remove unused dirent.d_reclen member

Remove the union around dirent.d_type and the unused dirent.d_reclen member
(which was necessary for compatibility with the MinGW dirent runtime, which
is no longer used).

Signed-off-by: Karsten Blees <blees@dcon.de>
Signed-off-by: Erik Faye-Lund <kusmabite@gmail.com>
Signed-off-by: Stepan Kasal <kasal@ucw.cz>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

compat/win32/dirent.h

@@ -10,10 +10,7 @@ typedef struct DIR DIR;
 
 struct dirent {
 	char d_name[FILENAME_MAX];       /* File name. */
-	union {
-		unsigned short d_reclen; /* Always zero. */
-		unsigned char  d_type;   /* Reimplementation adds this */
-	};
+	unsigned char d_type;      /* file type to prevent lstat after readdir */
 };
 
 DIR *opendir(const char *dirname);