[Bug 45320] cmd creates an environment variable with an empty name

https://bugs.winehq.org/show_bug.cgi?id=45320

--- Comment #12 from Dima Ryazanov  ---
Awesome, thanks, I'll test it now.

I've looked at the code - and I think you need to do the check when calculating
"count" and "len", too:

for (ptr = environ_strings; *ptr; ptr += strlen(ptr) + 1)
  {
    count++;
    len += strlen(ptr) + 1;
  }

Wasting a few bytes is probably not a big deal - but the doc string is pretty
explicit about the layout of the result:

* blk is an array of pointers to environment strings, ending with a NULL
 * and after that the actual copy of the environment strings, ending in a \0