Don't crash on startup of console programs in monolithic wxX11 build.

Don't crash on startup of console programs in monolithic wxX11 build.

When using monolithic build, GUI-specific wxWinModule is still linked in but
its initialization crashes because there is no global display. Simply don't do
anything in this module OnInit() in this case to avoid the problem (which
affected e.g. wxrc in this build configuration).

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@67678 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775