+#ifdef USE_ITHREADS
+# define OP_REFCNT_INIT MUTEX_INIT(&PL_op_mutex)
+# define OP_REFCNT_LOCK MUTEX_LOCK(&PL_op_mutex)
+# define OP_REFCNT_UNLOCK MUTEX_UNLOCK(&PL_op_mutex)
+# define OP_REFCNT_TERM MUTEX_DESTROY(&PL_op_mutex)
+#else
+# define OP_REFCNT_INIT NOOP
+# define OP_REFCNT_LOCK NOOP
+# define OP_REFCNT_UNLOCK NOOP
+# define OP_REFCNT_TERM NOOP
+#endif
+
+#define OpREFCNT_set(o,n) ((o)->op_targ = (n))
+#define OpREFCNT_inc(o) ((o) ? (++(o)->op_targ, (o)) : Nullop)
+#define OpREFCNT_dec(o) (--(o)->op_targ)
+
+/* flags used by Perl_load_module() */
+#define PERL_LOADMOD_DENY 0x1
+#define PERL_LOADMOD_NOIMPORT 0x2
+#define PERL_LOADMOD_IMPORT_OPS 0x4
+
+#ifdef USE_REENTRANT_API
+#include "reentr.h"
+#endif
+