MZ_Exec() patch, try 2

[Jukka Heinonen]

> This look more reasonable?

Yep. Only a few bugs left. Because cmdline buffer belongs
to the calling application you should not modify the
buffer. Use of memcpy or something like that would be 
recommended. Also, use of variable "status" is a mystery to
me. If CreateProcessA fails, it might not initialize handles
and even if it does not fail, they might be null handles 
(I don't know if that matters, though).

-- 
Jukka Heinonen <http://www.iki.fi/jhei/>