/* subprocess state */
PERLVAR(Ifdpid, AV *) /* keep fd-to-pid mappings for my_popen */
+#ifdef USE_THREADS
+PERLVAR(Ifdpid_mutex, perl_mutex) /* mutex for fdpid array */
+#endif
+
/* internal state */
PERLVAR(Itainting, bool) /* doing taint checks */
PERLVARI(Iop_mask, char *, NULL) /* masked operations for safe evals */