Fixes test failures on Vista.

It has apparently changed in Vista.

Fixes Quicken 2009. Aric said he added this hack back in 2002
to work around a bug in the IE6 installer, which installs fine
now without this hack.

Having three BOOL parameters looks a bit awkward.

The casts are already part of the CONTAINING_RECORD macro.

If the flag TCI_SRCFONTSIG is not set then the first argument passed
to TranslateCharsetInfo is just a DWORD that needs to be marshalled
over a pointer.