#92 gsoapWinInet: Add HTTP2 support

[mberchtold]

This code snippet adds HTTP2 support to the WinInet plugin:

In wininet_init, after InternetOpenA add:

#ifdef INTERNET_OPTION_ENABLE_HTTP_PROTOCOL
    DWORD httpProtocol = HTTP_PROTOCOL_FLAG_HTTP2;
    VERIFY(InternetSetOption(a_pData->hInternet, INTERNET_OPTION_ENABLE_HTTP_PROTOCOL, &httpProtocol, sizeof(httpProtocol)));
#endif

[mberchtold]

Correction: VERIFY should be removed as the feature is only available on Windows 10 and higher:

#ifdef INTERNET_OPTION_ENABLE_HTTP_PROTOCOL
    DWORD httpProtocol = HTTP_PROTOCOL_FLAG_HTTP2;
    InternetSetOption(a_pData->hInternet, INTERNET_OPTION_ENABLE_HTTP_PROTOCOL, &httpProtocol, sizeof(httpProtocol));
#endif

[Robert van Engelen]

Feature included with 2.8.26.