Provide a way to defer SIGINT handling in the current thread

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2017-09-07.20:03:25.096>
labels = ['interpreter-core', 'type-feature', '3.7']
title = 'Provide a way to defer SIGINT handling in the current thread'
updated_at = <Date 2019-08-07.08:13:45.053>
user = 'https://github.com/ncoghlan'

bugs.python.org fields:

activity = <Date 2019-08-07.08:13:45.053>
actor = 'jdemeyer'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Interpreter Core']
creation = <Date 2017-09-07.20:03:25.096>
creator = 'ncoghlan'
dependencies = []
files = []
hgrepos = []
issue_num = 31388
keywords = []
message_count = 12.0
messages = ['301622', '301625', '301627', '301665', '301690', '301692', '301693', '301703', '301705', '301726', '306224', '349154']
nosy_count = 6.0
nosy_names = ['gregory.p.smith', 'ncoghlan', 'pitrou', 'njs', 'jdemeyer', 'yselivanov']
pr_nums = []
priority = 'normal'
resolution = None
stage = 'needs patch'
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue31388'
versions = ['Python 3.7']