[issue37031] signalmodule.c: reuse runtime->main_thread

[STINNER Victor]

Change by STINNER Victor <vstinner at redhat.com>:


----------
keywords: +patch
pull_requests: +13452
stage:  -> patch review

_______________________________________
Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue37031>
_______________________________________