[Bug 36937] New: WinHttpReceiveRequest goes into infinite blocking on 304 responses

http://bugs.winehq.org/show_bug.cgi?id=36937

Bug ID: 36937
           Summary: WinHttpReceiveRequest goes into infinite blocking on
                    304 responses
           Product: Wine
           Version: 1.7.22
          Hardware: x86
                OS: Linux
            Status: UNCONFIRMED
          Severity: major
          Priority: P2
         Component: winhttp
          Assignee: [e-mail]
          Reporter: [e-mail]

Created attachment 49045
  --> http://bugs.winehq.org/attachment.cgi?id=49045
TestCase for the issue

When requesting a website with an "If-Modified-Since"-header and the website
returns "304 Not Modified" then the call to WinHttpReceiveResponse() blocks
forever.

The reason is that a 304-response does not have a Content-Length reader. For
some reason it gets set to 4096 and winhttp tries to read this many bytes from
the network even though nothing is going to come.

This bug affects the "Marvel Heroes 2015 Launcher" during update checking.
(Unfortunately game client still has some more issues)

Attach are a Testing-Program and a patch that fixes it.

(for the patch, I don't know if this would be the correct way to fix the issue,
but it looked like a good place to put the fix)