Bitfield Union does not work for bit widths greater than 8 bits

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2020-01-21.09:20:46.369>
labels = ['ctypes', 'type-bug', '3.7']
title = 'Bitfield Union does not work for bit widths greater than 8 bits'
updated_at = <Date 2020-01-23.07:49:15.925>
user = 'https://bugs.python.org/jschulte'

bugs.python.org fields:

activity = <Date 2020-01-23.07:49:15.925>
actor = 'ammar2'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['ctypes']
creation = <Date 2020-01-21.09:20:46.369>
creator = 'jschulte'
dependencies = []
files = ['48856']
hgrepos = []
issue_num = 39407
keywords = []
message_count = 1.0
messages = ['360372']
nosy_count = 5.0
nosy_names = ['vinay.sajip', 'amaury.forgeotdarc', 'belopolsky', 'meador.inge', 'jschulte']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue39407'
versions = ['Python 3.7']