This should not be encouraged, and it currently breaks cross-module
linking for qdoc.
With this in place, we can actually generated cross-references
downwards (e.g. from corelib to gui), although in a bit hackish way
at the moment.
Change-Id: I32919e04535464438e3bb83e41f9a40b752c71c6 Reviewed-by: Martin Smith <martin.smith@nokia.com>