#if defined(USE_ITHREADS)
PERLVAR(Gop_mutex, perl_mutex) /* Mutex for op refcounting */
+PERLVAR(Gsharedsv_space, PerlInterpreter*) /* The shared sv space */
+PERLVAR(Gsharedsv_space_mutex, perl_mutex) /* Mutex protecting the shared sv space */
#endif