PyAPI: add utilities PyTuple_SET_ITEMS, Py_INCREF_RET

Setting all values of a tuple is such a common operation that it deserves its own macro.
Also added Py_INCREF_RET to avoid confusing use of comma operator.

source/blender/python/generic/python_utildefines.h

@@ -0,0 +1,52 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file blender/python/generic/python_utildefines.h
+ *  \ingroup pygen
+ *  \brief header-only utilities
+ *  \note light addition to Python.h, use py_capi_utils.h for larger features.
+ */
+
+#ifndef __PYTHON_UTILDEFINES_H__
+#define __PYTHON_UTILDEFINES_H__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define PyTuple_SET_ITEMS(op_arg, ...) \
+{ \
+	PyTupleObject *op = (PyTupleObject *)op_arg; \
+	PyObject **ob_items = op->ob_item; \
+	CHECK_TYPE_ANY(op_arg, PyObject *, PyTupleObject *); \
+	BLI_assert(_VA_NARGS_COUNT(__VA_ARGS__) == PyTuple_GET_SIZE(op)); \
+	ARRAY_SET_ITEMS(ob_items, __VA_ARGS__); \
+} (void)0
+
+/* wrap Py_INCREF & return the result,
+ * use sparingly to avoid comma operator or temp var assignment */
+BLI_INLINE PyObject *Py_INCREF_RET(PyObject *op) { Py_INCREF(op); return op; }
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif  /* __PYTHON_UTILDEFINES_H__ */
+