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

[Marvin]

Hi,

While running your changed tests, I think I found new failures.
Being a bot and all I'm not very good at pattern recognition, so I might be
wrong, but could you please double-check?

Full results can be found at:
https://testbot.winehq.org/JobDetails.pl?Key=55703

Your paranoid android.


=== wvistau64_zh_CN (32 bit report) ===

vbscript:
run.c:1219: Test failed: api.vbs: L"Err.number = 0"

=== w7u (32 bit report) ===

vbscript:
run.c:1219: Test failed: api.vbs: L"Err.number = 0"