secur32: Simplify memory management by not allocating memory for the CredHandle and CtxtHandle pointers.

Instead store the handles directly in the SspiData structure and pass
the addresses of these into SSPI functions.

winex11.drv: Empty clipboard cache on process unload to avoid false positives being reported for memory leaks.

This reverts commit 8e729245.
Wine now requires a new enough flex version.

Revert "wrc: Use an EOF rule instead of lex_destroy for compatibility with prediluvian flex versions.".

This reverts commit 1405c00e.
Wine now requires a new enough flex version.

Wine needs a newer flex version than the prediluvian 2.5.4a.

We had to enable the Negotiate provider a while back so programs that expected 
that provider to be present would be happy. This broke programs that expect a 
Negotiate provider to actually do something if it is present. This fix works 
around that new issue by thunking all calls to Negotiate to NTLM.

Reported by Jacek Caban.