scorpionfly needs more semaphores

Hi,

We're seeing occasional failures like this:

running bootstrap script ... 2019-09-13 12:11:26.882 PDT [64926]
FATAL:  could not create semaphores: No space left on device
2019-09-13 12:11:26.882 PDT [64926] DETAIL:  Failed system call was
semget(5728001, 17, 03600).

I think you should switch to using "named" POSIX semaphores by
building with USE_NAMED_POSIX_SEMAPHORES (then it'll create a
squillion little files under /tmp and mmap() them), or increase the
number of SysV semaphores you can create with sysctl[1], or finish
writing your operating system[2] so you can switch to "unnamed" POSIX
semaphores :-)

[1] https://www.postgresql.org/message-id/flat/27582.1546928073%40sss.pgh.pa.us
[2] https://github.com/openbsd/src/blob/master/lib/librthread/rthread_sem.c#L112

-- 
Thomas Munro
https://enterprisedb.com