Add PythonCompatibility Codes for TSS (Thread Specific Storage) API

Cython/Utility/ModuleSetupCode.c

@@ -430,6 +430,40 @@ class __Pyx_FakeReference {
   #define __Pyx_PyThreadState_Current _PyThreadState_Current
 #endif
 
+// TSS (Thread Specific Storage) API
+#if PY_VERSION_HEX < 0x03070000 && !defined(PyThread_tss_create)
+#include "pythread.h"
+#define Py_tss_NEEDS_INIT 0
+typedef int Py_tss_t;
+static CYTHON_INLINE int PyThread_tss_create(Py_tss_t *key) {
+  *key = PyThread_create_key();
+  return 0; // PyThread_create_key reports success always
+}
+static CYTHON_INLINE Py_tss_t * PyThread_tss_alloc(void) {
+  Py_tss_t *key = (Py_tss_t *)PyObject_Malloc(sizeof(Py_tss_t));
+  *key = Py_tss_NEEDS_INIT;
+  return key;
+}
+static CYTHON_INLINE void PyThread_tss_free(Py_tss_t *key) {
+  PyObject_Free(key);
+}
+static CYTHON_INLINE int PyThread_tss_is_created(Py_tss_t *key) {
+  return *key != Py_tss_NEEDS_INIT;
+}
+static CYTHON_INLINE void PyThread_tss_delete(Py_tss_t *key) {
+  PyThread_delete_key(*key);
+  *key = Py_tss_NEEDS_INIT;
+}
+static CYTHON_INLINE int PyThread_tss_set(Py_tss_t *key, void *value) {
+  return PyThread_set_key_value(*key, value);
+}
+static CYTHON_INLINE void * PyThread_tss_get(Py_tss_t *key) {
+  return PyThread_get_key_value(*key);
+}
+// PyThread_delete_key_value(key) is equalivalent to PyThread_set_key_value(key, NULL)
+// PyThread_ReInitTLS() is a no-op
+#endif // TSS (Thread Specific Storage) API
+
 #if CYTHON_COMPILING_IN_CPYTHON || defined(_PyDict_NewPresized)
 #define __Pyx_PyDict_NewPresized(n)  ((n <= 8) ? PyDict_New() : _PyDict_NewPresized(n))
 #else