use PyImport_ExtendInittab for py module initialization rather then adding to sys.modules directly, no functional change.

source/blender/python/generic/mathutils.h

@@ -61,8 +61,7 @@ PyObject *BaseMathObject_getOwner( BaseMathObject * self, void * );
 PyObject *BaseMathObject_getWrapped( BaseMathObject *self, void * );
 void BaseMathObject_dealloc(BaseMathObject * self);
 
-PyObject *Mathutils_Init(void);
-PyObject *Noise_Init(void); /* lazy, saves having own header */
+PyMODINIT_FUNC BPyInit_mathutils(void);
 
 int EXPP_FloatsAreEqual(float A, float B, int floatSteps);
 int EXPP_VectorsAreEqual(float *vecA, float *vecB, int size, int floatSteps);