Otherwise, an IStream_SetSize call followed by an IStream_Read call 
could fail with STG_E_DOCFILECORRUPT.

It has a tendency to trigger X11 bugs, and it's not really useful anyway.

This lets ddraw dlls built on a machine with OpenGL present run on other 
machines that may not have the OpenGL libraries installed.

anybody had any doubts about what they actually do.

Also use the same code for Get/SetWindowWord.
Based on a patch by Ge van Geldorp.