This will allow accessing non-local declarations from debuggers, which,
AFAICT, was impossible before.
Getting scopes right already works for type declarations and functions,
but will need some fiddling for variables:

For those, I tried imitating what Clang does for static member
variables, but LLDB tries to re-mangle those and then fails at lookup,
while GDB outright crashes. Hopefully I can find some other dwarven
incantation to do the right thing.