functions to cproxy.c since both sets of functions depend on the
implementations of the standard stubs and proxies.

which seems to be more appropriate and matches the errno translation
in ntdll.

This shows that we have a vtbl ptr at (void**)This-2 that is passed to
the base interface's IRpcStubBuffer_Connect.  This vtbl should
presumably forward calls to the real object's vtbl.  We can't simply
pass the real object to the base interface's stub, as the real
object's QI may not provide us with the base interface.

quartz: Use the absolute height of the bitmap format as a negative values simply means it is a top-down bitmap.