revert r71159 since it broke the build

Include/object.h

@@ -749,13 +749,11 @@ PyAPI_FUNC(void) _Py_AddToAllObjects(PyObject *, int force);
 	((PyObject*)(op))->ob_refcnt++)
 
 #define Py_DECREF(op)					\
-	do {						\
-	    if (_Py_DEC_REFTOTAL  _Py_REF_DEBUG_COMMA	\
-		--((PyObject*)(op))->ob_refcnt != 0)	\
-		    _Py_CHECK_REFCNT(op)		\
-	    else					\
-		_Py_Dealloc((PyObject *)(op))		\
-        } while (0)
+	if (_Py_DEC_REFTOTAL  _Py_REF_DEBUG_COMMA	\
+	    --((PyObject*)(op))->ob_refcnt != 0)		\
+		_Py_CHECK_REFCNT(op)			\
+	else						\
+		_Py_Dealloc((PyObject *)(op))
 
 /* Safely decref `op` and set `op` to NULL, especially useful in tp_clear
  * and tp_dealloc implementatons.

Misc/NEWS

@@ -207,8 +207,6 @@ Core and Builtins
 - Issue #3845: In PyRun_SimpleFileExFlags avoid invalid memory access with
   short file names.
 
-- Py_DECREF: Add `do { ... } while (0)' to avoid compiler warnings.
-
 Library
 -------