create_unicode_buffer() gives different results on Windows vs Linux

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2019-12-26.10:54:39.715>
labels = ['ctypes', '3.8']
title = 'create_unicode_buffer() gives different results on Windows vs Linux'
updated_at = <Date 2019-12-26.10:54:39.715>
user = 'https://github.com/lazka'

bugs.python.org fields:

activity = <Date 2019-12-26.10:54:39.715>
actor = 'lazka'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['ctypes']
creation = <Date 2019-12-26.10:54:39.715>
creator = 'lazka'
dependencies = []
files = []
hgrepos = []
issue_num = 39137
keywords = []
message_count = 1.0
messages = ['358885']
nosy_count = 1.0
nosy_names = ['lazka']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = None
url = 'https://bugs.python.org/issue39137'
versions = ['Python 3.8']