Provide a fallback for QT_STAT_LNK on windows

In most cases, _S_IFLNK isn't defined, but ensure that we still have a
QT_STAT_LNK that works, for example for use around archive files
(zip/tar) that can contain symlinks

Change-Id: I9881e524b79845ce6b474b9a86e5fb25aaa31820
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: David Faure <david.faure@kdab.com>

mkspecs/win32-msvc2005/qplatformdefs.h

@@ -81,6 +81,8 @@
 #define QT_STAT_MASK		_S_IFMT
 #if defined(_S_IFLNK)
 #  define QT_STAT_LNK		_S_IFLNK
+#else
+#  define QT_STAT_LNK		0120000
 #endif
 #define QT_FILENO		_fileno
 #define QT_OPEN			::_open