Interaction between winbind and idmap and nss_info?

[Zen]

One of our build verification steps checks for imported symbols that are
never exported and we see failures such as...

File /usr/lib64/samba/libidmap-samba4.so contains unsatisfied symbols:
'find_domain_from_name',
'get_global_winbindd_state_offline',
'winbind_event_context'

And other similar ones for everything under /usr/lib64/samba/nss_info and
/usr/lib64/samba/idmap.

I notice on these libraries in the build file they all have
allow_undefined_symbols=True so based on that I assume this is how it is
supposed to be.

All the symbols it complains about are declared in winbindd_proto.h.

I built with --without-winbind so should these libraries just not have been
built at all? Do these libraries have a purpose without winbind?

Also to help me understand - are the functions in winbindd_proto.h called
via RPC/IPC?

Thanks