this is probably a historic relict. None of them should be used, and I cannot see any actual use of them either. The only non-library code that we link now is libosmo-gb (ns/bssgp), which soon will be turned into a real library.
The code corresponds to commit a9aa4777cc1144897a77dfb6c5c3d7325705251e in openbts-p2.8.git (Tue Jun 12 18:14:49 2012 +0400)