--- /dev/null
+From: Campbell Barton <ideasman42@gmail.com>
+Date: Mon, 22 Jun 2020 14:51:20 +1000
+Subject: fix_FTBFS_with_python3.9
+
+Resolves T78089, no functional changes.
+---
+ source/blender/python/mathutils/mathutils_Matrix.c | 16 +++++++++-------
+ source/blender/python/mathutils/mathutils_Quaternion.c | 14 ++++++++------
+ source/blender/python/mathutils/mathutils_Vector.c | 6 +++---
+ 3 files changed, 20 insertions(+), 16 deletions(-)
+
+diff --git a/source/blender/python/mathutils/mathutils_Matrix.c b/source/blender/python/mathutils/mathutils_Matrix.c
+index 7a3a92d..d380b61 100644
+--- a/source/blender/python/mathutils/mathutils_Matrix.c
++++ b/source/blender/python/mathutils/mathutils_Matrix.c
+@@ -42,7 +42,8 @@ static PyObject *Matrix_copy_notest(MatrixObject *self, const float *matrix);
+ static PyObject *Matrix_copy(MatrixObject *self);
+ static PyObject *Matrix_deepcopy(MatrixObject *self, PyObject *args);
+ static int Matrix_ass_slice(MatrixObject *self, int begin, int end, PyObject *value);
+-static PyObject *matrix__apply_to_copy(PyNoArgsFunction matrix_func, MatrixObject *self);
++static PyObject *matrix__apply_to_copy(PyObject *(*matrix_func)(MatrixObject *),
++ MatrixObject *self);
+ static PyObject *MatrixAccess_CreatePyObject(MatrixObject *matrix, const eMatrixAccess_t type);
+
+ static int matrix_row_vector_check(MatrixObject *mat, VectorObject *vec, int row)
+@@ -395,14 +396,15 @@ static PyObject *Matrix_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
+ return NULL;
+ }
+
+-static PyObject *matrix__apply_to_copy(PyNoArgsFunction matrix_func, MatrixObject *self)
++static PyObject *matrix__apply_to_copy(PyObject *(*matrix_func)(MatrixObject *),
++ MatrixObject *self)
+ {
+ PyObject *ret = Matrix_copy(self);
+ if (ret) {
+- PyObject *ret_dummy = matrix_func(ret);
++ PyObject *ret_dummy = matrix_func((MatrixObject *)ret);
+ if (ret_dummy) {
+ Py_DECREF(ret_dummy);
+- return (PyObject *)ret;
++ return ret;
+ }
+ else { /* error */
+ Py_DECREF(ret);
+@@ -1737,7 +1739,7 @@ PyDoc_STRVAR(
+ " .. note:: When the matrix cant be adjugated a :exc:`ValueError` exception is raised.\n");
+ static PyObject *Matrix_adjugated(MatrixObject *self)
+ {
+- return matrix__apply_to_copy((PyNoArgsFunction)Matrix_adjugate, self);
++ return matrix__apply_to_copy(Matrix_adjugate, self);
+ }
+
+ PyDoc_STRVAR(
+@@ -1945,7 +1947,7 @@ PyDoc_STRVAR(Matrix_transposed_doc,
+ " :rtype: :class:`Matrix`\n");
+ static PyObject *Matrix_transposed(MatrixObject *self)
+ {
+- return matrix__apply_to_copy((PyNoArgsFunction)Matrix_transpose, self);
++ return matrix__apply_to_copy(Matrix_transpose, self);
+ }
+
+ /*---------------------------matrix.normalize() ------------------*/
+@@ -1991,7 +1993,7 @@ PyDoc_STRVAR(Matrix_normalized_doc,
+ " :rtype: :class:`Matrix`\n");
+ static PyObject *Matrix_normalized(MatrixObject *self)
+ {
+- return matrix__apply_to_copy((PyNoArgsFunction)Matrix_normalize, self);
++ return matrix__apply_to_copy(Matrix_normalize, self);
+ }
+
+ /*---------------------------matrix.zero() -----------------------*/
+diff --git a/source/blender/python/mathutils/mathutils_Quaternion.c b/source/blender/python/mathutils/mathutils_Quaternion.c
+index 39d84c1..7ce0ea5 100644
+--- a/source/blender/python/mathutils/mathutils_Quaternion.c
++++ b/source/blender/python/mathutils/mathutils_Quaternion.c
+@@ -34,7 +34,8 @@
+
+ #define QUAT_SIZE 4
+
+-static PyObject *quat__apply_to_copy(PyNoArgsFunction quat_func, QuaternionObject *self);
++static PyObject *quat__apply_to_copy(PyObject *(*quat_func)(QuaternionObject *),
++ QuaternionObject *self);
+ static void quat__axis_angle_sanitize(float axis[3], float *angle);
+ static PyObject *Quaternion_copy(QuaternionObject *self);
+ static PyObject *Quaternion_deepcopy(QuaternionObject *self, PyObject *args);
+@@ -463,7 +464,7 @@ PyDoc_STRVAR(Quaternion_normalized_doc,
+ " :rtype: :class:`Quaternion`\n");
+ static PyObject *Quaternion_normalized(QuaternionObject *self)
+ {
+- return quat__apply_to_copy((PyNoArgsFunction)Quaternion_normalize, self);
++ return quat__apply_to_copy(Quaternion_normalize, self);
+ }
+
+ PyDoc_STRVAR(Quaternion_invert_doc,
+@@ -490,7 +491,7 @@ PyDoc_STRVAR(Quaternion_inverted_doc,
+ " :rtype: :class:`Quaternion`\n");
+ static PyObject *Quaternion_inverted(QuaternionObject *self)
+ {
+- return quat__apply_to_copy((PyNoArgsFunction)Quaternion_invert, self);
++ return quat__apply_to_copy(Quaternion_invert, self);
+ }
+
+ PyDoc_STRVAR(Quaternion_identity_doc,
+@@ -553,7 +554,7 @@ PyDoc_STRVAR(Quaternion_conjugated_doc,
+ " :rtype: :class:`Quaternion`\n");
+ static PyObject *Quaternion_conjugated(QuaternionObject *self)
+ {
+- return quat__apply_to_copy((PyNoArgsFunction)Quaternion_conjugate, self);
++ return quat__apply_to_copy(Quaternion_conjugate, self);
+ }
+
+ PyDoc_STRVAR(Quaternion_copy_doc,
+@@ -1385,10 +1386,11 @@ static PyObject *Quaternion_new(PyTypeObject *type, PyObject *args, PyObject *kw
+ return Quaternion_CreatePyObject(quat, type);
+ }
+
+-static PyObject *quat__apply_to_copy(PyNoArgsFunction quat_func, QuaternionObject *self)
++static PyObject *quat__apply_to_copy(PyObject *(*quat_func)(QuaternionObject *),
++ QuaternionObject *self)
+ {
+ PyObject *ret = Quaternion_copy(self);
+- PyObject *ret_dummy = quat_func(ret);
++ PyObject *ret_dummy = quat_func((QuaternionObject *)ret);
+ if (ret_dummy) {
+ Py_DECREF(ret_dummy);
+ return ret;
+diff --git a/source/blender/python/mathutils/mathutils_Vector.c b/source/blender/python/mathutils/mathutils_Vector.c
+index 6ea0dd5..c49cde8 100644
+--- a/source/blender/python/mathutils/mathutils_Vector.c
++++ b/source/blender/python/mathutils/mathutils_Vector.c
+@@ -96,10 +96,10 @@ static PyObject *Vector_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
+ return Vector_CreatePyObject_alloc(vec, size, type);
+ }
+
+-static PyObject *vec__apply_to_copy(PyNoArgsFunction vec_func, VectorObject *self)
++static PyObject *vec__apply_to_copy(PyObject *(*vec_func)(VectorObject *), VectorObject *self)
+ {
+ PyObject *ret = Vector_copy(self);
+- PyObject *ret_dummy = vec_func(ret);
++ PyObject *ret_dummy = vec_func((VectorObject *)ret);
+ if (ret_dummy) {
+ Py_DECREF(ret_dummy);
+ return (PyObject *)ret;
+@@ -376,7 +376,7 @@ PyDoc_STRVAR(Vector_normalized_doc,
+ " :rtype: :class:`Vector`\n");
+ static PyObject *Vector_normalized(VectorObject *self)
+ {
+- return vec__apply_to_copy((PyNoArgsFunction)Vector_normalize, self);
++ return vec__apply_to_copy(Vector_normalize, self);
+ }
+
+ PyDoc_STRVAR(Vector_resize_doc,