cygwin64 assertion failure

lorikeet seems to be stuck running the parallel tests, after having
failed an assertion.

Here's an excerpt from the log:

2016-10-09 11:52:35.751 EDT [57fa67c3.1148:11] LOG: statement: alter
table tenk1 set (parallel_workers = 4);
2016-10-09 11:52:35.753 EDT [57fa67c3.1148:12] LOG: statement: explain
(verbose, costs off)
select parallel_restricted(unique1) from tenk1
where stringu1 = 'GRAAAA' order by 1;
2016-10-09 11:52:35.756 EDT [57fa67c3.1148:13] LOG: statement: explain
(costs off)
select length(stringu1) from tenk1 group by length(stringu1);
2016-10-09 11:52:35.758 EDT [57fa67c3.1148:14] LOG: statement: select
length(stringu1) from tenk1 group by length(stringu1);
TRAP: FailedAssertion("!(vmq->mq_sender == ((void *)0))", File:
"/home/andrew/bf64/root/HEAD/pgsql.build/../pgsql/src/backend/storage/ipc/shm_mq.c",
Line: 221)
2016-10-09 11:53:54.260 EDT [57fa6795.2a7c:2] WARNING: worker took too
long to start; canceled

Since then almost the only thing on the log is repeated instances of
that last message.

cheers

andrew