Re: [HACKERS] intermittent failures in Cygwin from select_parallel tests

Today, lorikeet failed with a new variant on the bgworker start crash:

https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=lorikeet&dt=2017-06-21%2020%3A29%3A10

This one is even more exciting than the last one, because it sure looks
like the crashing bgworker took the postmaster down with it.  That is
Not Supposed To Happen.

Wondering if we broke something here recently, I tried to reproduce it
on a Linux machine by adding a randomized Assert failure in
shm_mq_set_sender.  I don't see any such problem, even with EXEC_BACKEND;
we recover from the crash as-expected.

So I'm starting to get a distinct feeling that there's something wrong
with the cygwin port.  But I dunno what.
        regards, tom lane