Re: [PATCH v3 0/3] MR5462: Ucrtbase's stderr is now always unbuffered.

[eric pouech (＠epo)]

eric pouech (@epo) commented about dlls/ucrtbase/tests/file.c:
> -
>    setvbuf(stdout, NULL, _IONBF, 0);
> -
> -
>    ok(ret == 4, "fprintf(stdout) returned %d\n", ret);
> -
>    ok(!pos, "expected stdout to be buffered\n");
> - }
> -
> - dup_fd = _dup(STDERR_FILENO);
> - if (dup_fd != -1)
> - {
> -
>    file = freopen("std_stream_test.tmp", "w", stderr);
> -
>    ok(file != NULL, "freopen failed\n");
> -
> -
>    ret = fprintf(stderr, "test");
> -
>    ok(ret == 4, "fprintf(stderr) returned %d\n", ret);
> -
>    pos = _telli64(STDERR_FILENO);
> -
>    ok(pos == 4 || broken(!GetProcAddress(GetModuleHandleA("ucrtbase"), "__CxxFrameHandler4") && !pos),

this will only be tested on x86_64 (the assumption that the buffering is orthogonal to the machine seems reasonable, but remains to be tested for future native ucrtbase versions)
perhaps we could do something like:
```
if (broken(!GetProcAddress(GetModuleHandleA("ucrtbase"), "__CxxFrameHandler4") && !pos))
    trace("stderr is unbuffered\n");
else
    ok(pos == 4, ...
```