The oleauto.h file that is part of the w32api 2.0
release has a prototype for DeregisterTypeLib() but no
prototype for UnRegisterTypeLib(). The oleaut32.a
library implements UnRegisterTypeLib() and has nothing
for DeregisterTypeLib(). The prototype for
DeRegisterTypeLib() needs to be added to oleauto.h,
perhaps replacing DeregisterTypeLib.
I found this problem while adding OLE support to the
Vim Mingw makefile. Vim currently gets a compile error
due to the missing function prototype.