[2.7] bpo-33015: Fix UB in pthread PyThread_start_new_thread (GH-6008) by vstinner · Pull Request #10823 · python/cpython
Fix an undefined behaviour in the pthread implementation of
PyThread_start_new_thread(): add a function wrapper to always return
NULL.
Add pythread_callback struct and pythread_wrapper() to thread_pthread.h.
(cherry picked from commit 9eea6ea)