issue 4014: output debug info for all referenced classes/structs and enumerators

This patch outputs full debug info for anything that is referenced, not only for declaration in modules on the command line. Leave it to the linker to filter out duplicates.

In toobj.c, it might also be possible to just leave out the call to toDebug()/toCtype(), because the debug info will always end up where the declaration is used.

The patch in cgcv.c was necessary, because it crashed on some debug info for me. Is the hack still necessary?

bugzilla: http://d.puremagic.com/issues/show_bug.cgi?id=4014