Thanks for the reply and the fix -- I have not tried the master branch, but will try to do that soon. If I understand correctly, we will have to stick with our kludgy "workaround" version in order to work with Python 3.7.6 and 3.8.1.  Or is there a better approach than our workaround of using

class access_rights_handler_args(ctypes.Structure):
    "access rights arguments"
    _fields_ = [('chid', ctypes.c_long),
                ('access', ctypes.c_ubyte)]

?   

As a long-time (20 years) Python user and first-time reporter of a bug to main Python, I'm both very appreciative of the effort and slightly alarmed by reading the messages related to #16575.  From far outside the Python dev world, it appears that an old, poorly verified bug report inspired a change that was actually not well tested and so incorrectly broke valid code without deprecation. Trying to be as polite as possible, this appears to indicate a poor testing process, if not a poor understanding of the actual code in question. 

Trust is an important aspect of open source software, and much easier to lose than gain.  I strongly encourage you and other Python devs to carefully assess what went wrong here and to work out (and write down) what will be done going forward to avoid such problems. Simply rolling this change back and saying "sorry, but we're overworked volunteers and stuff happens" is not going to regain lost trust. In fact, it's pretty close to a promise that this sort of issue will happen again. I think that you may want to make sure that it is not the take-away message here.
Sorry if that sounds in any way unappreciative.  Thanks.