Threading and THREAD_SAFE for AIX

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2019-05-22.12:01:09.176>
labels = ['build', '3.8', '3.9', '3.10']
title = 'Threading and THREAD_SAFE for AIX'
updated_at = <Date 2020-11-18.10:12:55.031>
user = 'https://github.com/aixtools'

bugs.python.org fields:

activity = <Date 2020-11-18.10:12:55.031>
actor = 'christian.heimes'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Build']
creation = <Date 2019-05-22.12:01:09.176>
creator = 'Michael.Felt'
dependencies = []
files = []
hgrepos = []
issue_num = 37009
keywords = []
message_count = 3.0
messages = ['343184', '365359', '365898']
nosy_count = 3.0
nosy_names = ['Michael.Felt', 'kadler', 'BTaskaya']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = None
url = 'https://bugs.python.org/issue37009'
versions = ['Python 3.8', 'Python 3.9', 'Python 3.10']