MCopyc2pWindow Sourcec2pWindow.w,Destc2pWindow.w ; Copy definition-data only

Duplicates an existing c2pWindow object into a new one. As c2pWindows do not
contain any graphics data, the c2pWindow's definition data describing the size of
the operation only is copied, so is effectively just a `clone' of the original.
You may want to use this in conjunction with MNewc2pWindowHeight.