PERLVAR(Gnthreads, int) /* Number of threads currently */
PERLVAR(Gthreads_mutex, perl_mutex) /* Mutex for nthreads and thread list */
PERLVAR(Gnthreads_cond, perl_cond) /* Condition variable for nthreads */
+PERLVAR(Gsvref_mutex, perl_mutex) /* Mutex for SvREFCNT_{inc,dec} */
PERLVARI(Gthreadsv_names, char *, THREADSV_NAMES)
#ifdef FAKE_THREADS
PERLVAR(Gcurthr, struct perl_thread *) /* Currently executing (fake) thread */