Introduce cast macros

Author: picnixz

Modules/_decimal/_decimal.c

@@ -178,11 +178,15 @@ typedef struct {
     mpd_uint_t data[_Py_DEC_MINALLOC];
 } PyDecObject;
 
+#define _PyDecObject_CAST(op)   ((PyDecObject *)(op))
+
 typedef struct {
     PyObject_HEAD
     uint32_t *flags;
 } PyDecSignalDictObject;
 
+#define _PyDecSignalDictObject_CAST(op) ((PyDecSignalDictObject *)(op))
+
 typedef struct PyDecContextObject {
     PyObject_HEAD
     mpd_context_t ctx;
@@ -193,12 +197,16 @@ typedef struct PyDecContextObject {
     decimal_state *modstate;
 } PyDecContextObject;
 
+#define _PyDecContextObject_CAST(op)    ((PyDecContextObject *)(op))
+
 typedef struct {
     PyObject_HEAD
     PyObject *local;
     PyObject *global;
 } PyDecContextManagerObject;
 
+#define _PyDecContextManagerObject_CAST(op) ((PyDecContextManagerObject *)(op))
+
 #undef MPD
 #undef CTX
 #define PyDec_CheckExact(st, v) Py_IS_TYPE(v, (st)->PyDec_Type)