llvm: encode variables as DW_TAG_imported_declaration

Now we get working global variable lookup in GDB! LLDB still re-mangles,
and it looks like we can't do much about that for now.

Also: translate non-owning type declarations into typedefs.
359bbdd574Tau committed on 7/19/2024, 3:51:37 PMparent876258a
3 files changedLine totals unavailable