python 3.9.1 failed to create .so files as universal2 (arm64, x86_64) on Mac

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2020-12-11.10:34:20.355>
labels = ['OS-mac', 'build', '3.9', '3.10']
title = 'python 3.9.1 failed to create .so files as universal2 (arm64, x86_64) on Mac'
updated_at = <Date 2021-01-10.10:34:42.964>
user = 'https://bugs.python.org/xzsophos'

bugs.python.org fields:

activity = <Date 2021-01-10.10:34:42.964>
actor = 'ronaldoussoren'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['macOS']
creation = <Date 2020-12-11.10:34:20.355>
creator = 'xz_sophos'
dependencies = []
files = []
hgrepos = []
issue_num = 42619
keywords = ['patch']
message_count = 4.0
messages = ['382861', '382862', '384757', '384758']
nosy_count = 3.0
nosy_names = ['ronaldoussoren', 'ned.deily', 'xz_sophos']
pr_nums = ['24187']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'compile error'
url = 'https://bugs.python.org/issue42619'
versions = ['Python 3.9', 'Python 3.10']