https://bugs.winehq.org/show_bug.cgi?id=43315
--- Comment #4 from mrdeathjr28@yahoo.es --- (In reply to Kimmo Myllyvirta from comment #1)
Created attachment 58657 [details] quick fix
This is related to WSAIoctl, SIO_GET_EXTENSION_FUNCTION_POINTER. The call is successful, but Steam compares if cbBytesReturned < 4, and it fails since wine sets it to 0. Not sure how correct the attached patch is, but at least Steam starts with it.
Confirmed with patch steam back to work