Cygwin: proc fd: pass along open mode when reopening file

The reopen code neglected to pass along the requested open
mode correctly.  This may end up reopening the file with
incorrect access mask, or duplicating the wrong pipe handle.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

winsup/cygwin/fhandler.cc

@@ -792,7 +792,7 @@ done:
 }
 
 fhandler_base *
-fhandler_base::fd_reopen (int)
+fhandler_base::fd_reopen (int, mode_t)
 {
   /* This is implemented in fhandler_process only. */
   return NULL;