mciavi: In MCI, RECT structure is used differently: rc.right = width & rc.bottom = height so do the conversion when needed.

The memory is uninitialised and so further unmarshalling shouldn't try
to reuse any memory. fMustAlloc is always set to TRUE when allocating
memory so that it is clear that the unmarshalling is safe and to avoid
future problems with change or the code being copied.

Avoids a warning of a memory leak in Valgrind.

There is no need to cast the pointers passed to the penultimate
argument of the CryptDecodeObjectEx and CryptEncodeObjectEx functions
as those expect void pointers.

This prevents fallout from the GL_EXT_fog_coord emulation. glEnable
and glDisable calls other than those that change GL_FOG are not
hooked. The glEnableWINE and glDisableWINE functions can be used to
add other hooks too if ever needed.

The fog doesn't depend on pixel shaders any longer(but still vice
versa), so we don't need this state any more.

This is the "replacement" for the fog coord optimization removed in
the previous patch.