[PATCH 4/4] vbscript: Fix handling null argument in CStr.

[Jacek Caban]

Signed-off-by: Jacek Caban <jacek(a)codeweavers.com>
---
  dlls/vbscript/global.c      | 3 +++
  dlls/vbscript/tests/api.vbs | 8 ++++++++
  2 files changed, 11 insertions(+)