The usage of the lib pointer was cryptic to say the least, it was
essentialy used to allow or not local IDs results in the mapping
old_id_pointer -> new_id_pointer lookup result.
Now:
- Explicitely pass a boolean to allow or not local ID as result in
lower-level code.
- Pass the 'self ID' pointer instead of its library to the whole
liblinking code (that was already the case in a few places).
Note that naming of the 'self id' pointer is currently very inconsistent
throughout the readfile liblink code, this will have to be cleaned up in
a separate step later. For now, `self_id` has been chosen for new code
as it matches the terminology in lib_query code.
The later change can also allow finer handling of lookup on undo, based
on how it was re-read (or not), should the need for this arise.