brei: move the object_id_t typedefs to the brei-proto.h header (and another other warning fixes)
Fixes some remaining clang warnings.
Fixes #31 (closed)
edit: had to drop the commit to remove the -Wstringop-truncation
pragma bits, turns out at least in the CI pipeline gcc still fails without those. Might be a gcc version update (CI is on F37, I'm no F38 here), needs triage.
Edited by Peter Hutterer