+#ifndef mPUSHp
+# define mPUSHp(P, L) PUSHs(sv_2mortal(newSVpvn((P), (L))))
+#endif
+
+#ifndef mPUSHu
+# define mPUSHu(U) PUSHs(sv_2mortal(newSVuv(U)))
+#endif
+
+#ifndef HvNAME_get
+# define HvNAME_get(H) HvNAME(H)
+#endif
+
+#ifndef HvNAMELEN_get
+# define HvNAMELEN_get(H) strlen(HvNAME_get(H))
+#endif
+
+#define I_HAS_PERL(R, V, S) (PERL_REVISION > (R) || (PERL_REVISION == (R) && (PERL_VERSION > (V) || (PERL_VERSION == (V) && (PERL_SUBVERSION >= (S))))))
+
+#if I_HAS_PERL(5, 10, 0) || defined(PL_parser)
+# ifndef PL_lex_inwhat
+# define PL_lex_inwhat PL_parser->lex_inwhat
+# endif
+# ifndef PL_linestr
+# define PL_linestr PL_parser->linestr
+# endif
+# ifndef PL_bufptr
+# define PL_bufptr PL_parser->bufptr
+# endif
+# ifndef PL_oldbufptr
+# define PL_oldbufptr PL_parser->oldbufptr
+# endif
+#else
+# ifndef PL_lex_inwhat
+# define PL_lex_inwhat PL_Ilex_inwhat
+# endif
+# ifndef PL_linestr
+# define PL_linestr PL_Ilinestr
+# endif
+# ifndef PL_bufptr
+# define PL_bufptr PL_Ibufptr
+# endif
+# ifndef PL_oldbufptr
+# define PL_oldbufptr PL_Ioldbufptr
+# endif
+#endif
+
+#ifndef I_WORKAROUND_REQUIRE_PROPAGATION
+# define I_WORKAROUND_REQUIRE_PROPAGATION !I_HAS_PERL(5, 10, 1)
+#endif
+
+/* ... Thread safety and multiplicity ...................................... */
+
+/* Safe unless stated otherwise in Makefile.PL */
+#ifndef I_FORKSAFE
+# define I_FORKSAFE 1
+#endif
+
+#ifndef I_MULTIPLICITY
+# if defined(MULTIPLICITY) || defined(PERL_IMPLICIT_CONTEXT)
+# define I_MULTIPLICITY 1
+# else
+# define I_MULTIPLICITY 0
+# endif
+#endif
+#if I_MULTIPLICITY && !defined(tTHX)
+# define tTHX PerlInterpreter*
+#endif
+
+#if I_MULTIPLICITY && defined(USE_ITHREADS) && defined(dMY_CXT) && defined(MY_CXT) && defined(START_MY_CXT) && defined(MY_CXT_INIT) && (defined(MY_CXT_CLONE) || defined(dMY_CXT_SV))
+# define I_THREADSAFE 1
+# ifndef MY_CXT_CLONE
+# define MY_CXT_CLONE \
+ dMY_CXT_SV; \
+ my_cxt_t *my_cxtp = (my_cxt_t*)SvPVX(newSV(sizeof(my_cxt_t)-1)); \
+ Copy(INT2PTR(my_cxt_t*, SvUV(my_cxt_sv)), my_cxtp, 1, my_cxt_t); \
+ sv_setuv(my_cxt_sv, PTR2UV(my_cxtp))
+# endif
+#else
+# define I_THREADSAFE 0
+# undef dMY_CXT
+# define dMY_CXT dNOOP
+# undef MY_CXT
+# define MY_CXT indirect_globaldata
+# undef START_MY_CXT
+# define START_MY_CXT STATIC my_cxt_t MY_CXT;
+# undef MY_CXT_INIT
+# define MY_CXT_INIT NOOP
+# undef MY_CXT_CLONE
+# define MY_CXT_CLONE NOOP
+#endif
+
+/* --- Helpers ------------------------------------------------------------- */
+
+/* ... Thread-safe hints ................................................... */
+
+#if I_WORKAROUND_REQUIRE_PROPAGATION
+
+typedef struct {
+ SV *code;
+ IV require_tag;
+} indirect_hint_t;
+
+#define I_HINT_STRUCT 1
+
+#define I_HINT_CODE(H) ((H)->code)
+
+#define I_HINT_FREE(H) { \
+ indirect_hint_t *h = (H); \
+ SvREFCNT_dec(h->code); \
+ PerlMemShared_free(h); \