bpo-31893: Fix errors in b9052a0f91d2e83bbc27267247a5920c82b242a3. (GH-4196) (#4202)

* Fix a compilation error on FreeBSD.
* Fix the data attribute size on Mac OS X.
(cherry picked from commit 2298fad5ff907dd48ea0fb5c71fa22334ef28c6b)
1 file changed