Created originally on Bitbucket by msabramo (Marc Abramowitz)
Was already merged in Bitbucket before import, marked as merged by the import user
Add test_SetFromErrnoWithFilename_NULL
Tests that PyErr_SetFromErrnoWithFilename
with filename == NULL
works.
A prelude to refactoring PyErr_SetFromErrnoWithFilename
to use PyErr_SetFromErrnoWithFilenameObject
which was just added in PR #211 (closed).