+#ifdef DEBUGGING
+ {
+ const char *s = PerlEnv_getenv("PERL_DESTRUCT_LEVEL");
+ if (s) {
+ int i;
+#if VMG_HAS_PERL(5, 21, 3)
+ if (strEQ(s, "-1")) {
+ i = -1;
+ } else {
+# if VMG_HAS_PERL(5, 21, 10)
+ UV uv;
+ if (Perl_grok_atoUV(s, &uv, NULL) && uv <= INT_MAX)
+ i = (int) uv;
+ else
+ i = 0;
+# else /* VMG_HAS_PERL(5, 21, 3) && !VMG_HAS_PERL(5, 21, 10) */
+ i = Perl_grok_atou(s, NULL);
+# endif
+ }
+#else /* !VMG_HAS_PERL(5, 21, 3) */
+ i = atoi(s);
+#endif
+ if (lvl < i)
+ lvl = i;
+ }
+ }
+#endif
+
+ return lvl;
+}
+
+static void vmg_global_teardown(pTHX_ void *root) {
+ if (!vmg_initialized)
+ return;
+
+#if VMG_MULTIPLICITY
+ if (aTHX != root)
+ return;
+#endif
+
+ if (vmg_destruct_level() == 0) {
+ vmg_global_teardown_late();
+ } else {
+ if (!PL_strtab)
+ PL_strtab = newHV();
+ vmg_sv_magicext((SV *) PL_strtab, NULL, &vmg_global_teardown_vtbl, NULL, 0);
+ }
+
+ return;
+}
+
+static void vmg_global_setup(pTHX) {
+#define vmg_global_setup() vmg_global_setup(aTHX)
+ if (vmg_initialized)
+ return;
+
+#if VMG_THREADSAFE
+ MUTEX_INIT(&vmg_vtable_refcount_mutex);
+ MUTEX_INIT(&vmg_op_name_init_mutex);
+#endif
+
+#if VMG_MULTIPLICITY
+ call_atexit(vmg_global_teardown, aTHX);
+#else
+ call_atexit(vmg_global_teardown, NULL);
+#endif
+
+ vmg_initialized = 1;
+
+ return;
+}
+
+/* --- Interpreter setup/teardown ------------------------------------------ */
+
+static void vmg_local_teardown(pTHX_ void *param) {
+ dMY_CXT;
+
+ if (MY_CXT.depth == 0 && MY_CXT.freed_tokens) {
+ vmg_magic_chain_free(MY_CXT.freed_tokens, NULL);
+ MY_CXT.freed_tokens = NULL;
+ }
+
+ return;
+}
+
+static void vmg_local_setup(pTHX) {
+#define vmg_local_setup() vmg_local_setup(aTHX)