Noticed by Barnabás Virágh as a python-3.7 failue on qemu-alpha.
The bug shows up on alpha as it's one of the targets where
EPOLL_CLOEXEC differs from other targets:
sysdeps/unix/sysv/linux/alpha/bits/epoll.h: EPOLL_CLOEXEC = 01000000
sysdeps/unix/sysv/linux/bits/epoll.h: EPOLL_CLOEXEC = 02000000