misc minor changes

- make cmake osx use of -ftemplate-depth match scons.
- use array size within sizeof(), more compact.
- replace AT with __func__ where the function is unique enough.
- BLI_box_pack_2D -> 2d to match other functions.
- rename new mesh normal calculation to mesh.calc_normals_split()

source/blender/python/mathutils/mathutils_geometry.c

@@ -1493,7 +1493,7 @@ static PyObject *M_Geometry_box_pack_2d(PyObject *UNUSED(self), PyObject *boxlis
 		}
 
 		/* Non Python function */
-		BLI_box_pack_2D(boxarray, len, &tot_width, &tot_height);
+		BLI_box_pack_2d(boxarray, len, &tot_width, &tot_height);
 
 		boxPack_ToPyObject(boxlist, &boxarray);
 	}