(td_thr_tlsbase): Declare it. * td_thr_tlsbase.c: New file. * Makefile (libthread_db-routines): Add it. * Versions (libthread_db: GLIBC_2.3.3): New set, add td_thr_tlsbase. * td_thr_tls_get_addr.c (td_thr_tls_get_addr): Use td_thr_tlsbase.