Re: Preventing abort() and exit() calls in libpq

I wrote:
>> This relies on "nm" being able to work on shlibs, which it's not
>> required to by POSIX. However, it seems to behave as desired even
>> on my oldest dinosaurs. In any case, if "nm" doesn't work then
>> we'll just not detect such problems on that platform, which should
>> be OK as long as the test does work on common platforms.

So I pushed that, and not very surprisingly, it's run into some
portability problems. gombessa (recent OpenBSD) reports

! nm -A -g -u libpq.so.5.15 2>/dev/null | grep -v '_eprintf\\.o:' | grep -e abort -e exit
libpq.so.5.15:__cxa_atexit

So far as I can find, __cxa_atexit is a C++ support routine, so
I wondered what the heck libpq.so is doing calling it. I managed
to reproduce the failure here using an OpenBSD installation I had
at hand, and confirmed that __cxa_atexit is *not* referenced by any
of the .o files in src/port, src/common, or src/interfaces/libpq.
So apparently it's being injected at some fairly low level of the
shlib support on that platform.

Probably the thing to do is adjust the grep filter to exclude
__cxa_atexit, but I want to wait awhile and see whether any
other buildfarm animals report this. morepork at least will
be pretty interesting, since it's a slightly older OpenBSD
vintage.

regards, tom lane