crt: test: In t_stat_slash.c turn off buffering for stdout

Signed-off-by: LIU Hao <lh_mouse@126.com>

mingw-w64-crt/testcases/t_stat_slash.c

diff --git a/mingw-w64-crt/testcases/t_stat_slash.c b/mingw-w64-crt/testcases/t_stat_slash.c
index ec08c31..9e335e3 100644
--- a/mingw-w64-crt/testcases/t_stat_slash.c
+++ b/mingw-w64-crt/testcases/t_stat_slash.c
@@ -31,7 +31,9 @@
 {
   wchar_t windir_wbuf[MAX_PATH + 1];
   char windir_abuf[MAX_PATH + 1];
-  
+
+  setvbuf (stdout, NULL, _IONBF, 0);
+
   if (GetWindowsDirectoryA(&windir_abuf[0], MAX_PATH))
   {
     strcat (&windir_abuf[0], "\\");