Re: BUG #17083: [PATCH] PostgreSQL fails to build with OpenLDAP 2.5.x

Michael Paquier <michael(at)paquier(dot)xyz> writes:
> On Thu, Jul 08, 2021 at 09:53:11AM +0200, Daniel Gustafsson wrote:
>> Couldn't we add a version check to find if we have < 2.5 or >= 2.5, and adjust
>> libs accordingly? Alternatively we could perhaps check for
>> LDAP_API_FEATURE_X_OPENLDAP_REENTRANT which IIUC when set defines -lldap to be
>> reentrant.

> Would you fetch the version number directly from the library?

Yeah, that all sounds kind of fragile.

On investigation it seems that libldap_r has been around basically
forever. Even my second-oldest buildfarm animal prairiedog has got
it (indeed libldap.dylib and libldap_r.dylib are symlinks to
the same file on that platform ... hmm). My oldest animal gaur
is irrelevant to this discussion, because we don't support
--enable-thread-safety on it in the first place.

That being the case, I think we might be okay just going with the
solution in Adrian's last patch, ie use libldap_r if it's there
and otherwise assume that libldap is thread-safe. It looks
fairly unlikely that anyone will ever have an issue with that;
while if we complicate the configure probe, we might be introducing
new problems just from that.

regards, tom lane