Remove cyrefcount old utility code

Cython/Utility/ModuleSetupCode.c

@@ -1517,53 +1517,3 @@ static void __Pyx_FastGilFuncInit(void) {
 }
 
 #endif
-
-/////////////// CythonExtensionTypes ///////////////
-
-#if !defined(__GNUC__)
-#define GCC_VERSION (__GNUC__ * 10000 \
-                     + __GNUC_MINOR__ * 100 \
-                     + __GNUC_PATCHLEVEL__)
-/* Test for GCC > 4.9.0 */
-#if GCC_VERSION < 40900
-#error atomic.h works only with GCC newer than version 4.9
-#endif /* GNUC >= 4.9 */
-
-#endif /* Has GCC */
-
-#ifdef __cplusplus
-  #if __cplusplus >= 201103L
-    #include <atomic>
-    using namespace std;
-    #define CyObject_ATOMIC_REFCOUNT_TYPE atomic_int
-
-    class CyObject {
-        private:
-          CyObject_ATOMIC_REFCOUNT_TYPE ob_refcnt;
-        public:
-          CyObject(): ob_refcnt(1) {}
-          virtual ~CyObject() {}
-          void CyObject_INCREF();
-          int CyObject_DECREF();
-    };
-
-    static inline int _Cy_DECREF(CyObject *op) {
-        return op->CyObject_DECREF();
-    }
-
-    static inline void _Cy_INCREF(CyObject *op) {
-        op->CyObject_INCREF();
-    }
-
-    /* Cast argument to CyObject* type. */
-    #define _CyObject_CAST(op) op
-
-    #define Cy_INCREF(op) do {if (op != NULL) {_Cy_INCREF(_CyObject_CAST(op));}} while(0)
-    #define Cy_DECREF(op) do {if (_Cy_DECREF(_CyObject_CAST(op))) {op = NULL;}} while(0)
-    #define Cy_XDECREF(op) do {if (op != NULL) {Cy_DECREF(op);}} while(0)
-    #define Cy_GOTREF(op)
-    #define Cy_XGOTREF(op)
-    #define Cy_GIVEREF(op)
-    #define Cy_XGIVEREF(op)
-  #endif
-#endif

Cython/Utility/ObjectHandling.c

@@ -1581,31 +1581,6 @@ try_unpack:
     return 0;
 }
 
-/////////////// CythonReferenceCounting.proto ///////////////
-
-#ifdef __cplusplus
-  #include <cstdlib>
-  #include <cstddef>
-// atomic is already included in ModuleSetupCode
-//  #include <atomic>
-#else
-  #error C++ needed for cython+ nogil classes
-#endif /* __cplusplus */
-
-void CyObject::CyObject_INCREF()
-{
-  atomic_fetch_add(&(this->ob_refcnt), 1);
-}
-
-int CyObject::CyObject_DECREF()
-{
-  if (atomic_fetch_sub(&(this->ob_refcnt), 1) == 1) {
-    delete this;
-    return 1;
-  }
-  return 0;
-}
-
 
 /////////////// UnpackUnboundCMethod.proto ///////////////